Guys, for all of those who are confused, this might be an easier solution...... It states there that Nazrat is 4 years older then Umaima so x + 4 and x will be Umaima. 2 years ago, Nazrat was 5 times as old as Umaima , first before solving for the equation, you need to minus the 4 by 2 because it says 2 years ago then it becomes x - 2 and so x (Umaima) becomes x - 2 as well and it also states there that Nazrat is 5 times older then Umaima 2 years ago and this is where you times the age of Umaima two years ago by 5 so the equation will be: x +2 = (x - 2)5 x + 2= 5x - 10 x - 5x = -10 - 2 -4x = -12 -4x/-1 = -12/-1 4x = 12 x = 3 ( Remember that x is Umaima's age and the age of Nazrat is 4 years older than Umaima) The age of Nazrat is 7 because x + 3 and the age of Umaima
That is the reason why you put everything in a table and make the table the same way every time. It is tough to keep track of everything mentally so that's the reason for the table.
i'm still having quite a hard time solving these problems, specially because we're doing online distance learning. i am so confused and stressed iver this topic, and the deadline for the summative test is so near. 😔
found a different (more intuitive for me) approach with the same result: N = U + 4 N - 2 = 5(U - 2) substitute the first N into the second equation: U + 4 - 2 = 5U - 10 12 = 4U U = 3, therefore N = 7
there's another way of doing it, though I'm pretty sure you already know it Sal N = U+4 [N is 4 years older than U] N-2 = 5(U-2) [2 years ago N was 5 times as old as U] U+4-2 = 5(U-2) [using the 2nd equation, substitute N with U+4(from first equation)] U+2 = 5U-10 [solve] U-5U = -10-2 -4U = -12 -4U/-4 = -12/-4 U = 3 N = U+4 N = 3+4 N = 7
Well... That's not how I got it.. from 1st info I got the following equation: N = 4 + U from 2nd info I got: N - 2 = 5 ( U - 2 ) then I replaced the value of N from the earlier equation to be: 4 + U - 2 = 5U - 10 4 - 2 + 10 = 5U - U U = 3 and N = 7 But you are great I love your videos....
Very confusing because it makes sense for the 5 to go into the Naz box BUT since we want to make an equation, the 5 goes into the Umaima box thus x-2 = 5(x-6)
The first question was trial and error it couldn't have been more than 3 bc then the numbers differences would have become larger. The answer was 2 years 2+4=6 and 6÷3=2 so ya really obvious to be honest idk if that's what u guys think
Could you help me with this problem teacher. Antonio is as old as the combined ages of his two brothers Bendito and Cristiano. But Cristiano is two years older than Bendito. The combined ages of three last year was 3/4 the combined ages at present. How old is Bendito now?
This solution only satisfies the limits of the equation. A reality check, as he likes to say, does not uphold his solution. His current age is an open ended statement. If he started off at twelve, then the equation changes. This equation only satisfies what his new age could be in 4 years, not his current age. If this was on a test the correct answer would be not enough information given!
3 times as old For example If he was 5 and in 4 years he will be 9 But he cant be 5 since if he was 3 times as old he would be 15 So 2 He is 2 today and if he will be 6 in 4 years 6 year olds is 3 times as old as 2 year olds
I find it easier, when making a table, to put times in the past to the left, and times in the future to the right. It's just like the number line, where negative numbers are on the left, the zero in the middle, and the positive numbers on the right. It keeps me from getting confused and mixing up variables. In this case, I would put (-2 years) in the left-hand column, and (Now) or (zero years) in the right-hand column. I do this because there are harder age problems that mention the present, the past, AND the future. In that case I'd put the past (in negative years) in the left-hand column, the present (or zero years) in the middle column, and the future (in positive years) in the right-hand column. I think the key is to do it the same way every time.
isn't x-5x=-4x? Sal put down positive 4x. I mean, it eventually becomes a positive number by following steps from there, so is it just a time saving thing?
i disagree with derek. he is clear when he's talking but it's difficult to draw clearly on an online blackboard. i find it quite easy to follow and extremely helpful. that was funny though.."let me figure out how to turn this thing off"
Easy. You don't even need a table for such a simple problem. Set the mother's age to (x), and Revathi's age to (x/3). The 'difference' in age is just another way of saying that you subtract them. (x - x/3) = 2x/3. We know that the difference is 24 years, because that is given in the problem. So 2x/3 = 24. If we multiply both sides by (3/2), we get 1x, which is what we want. x = 36. The mother is 36 years old, and Revathi's age is 12. We can check the answers easily. The problem says that Revathi's age is 1/3 of her mother's age. 12/36 reduces to 1/3, so that is correct. The problem also states that the difference in age is 24 years. The mother's age (36) minus Revathi's age (12) equals 24 years. Our answer must be correct.
The first example with Ali of course "makes sence" and of course it works out and of course the result is correct, but it`s completely unexplained how you somehow just arbitrarily set X to 2. Where is the formular to repeat it with different numbers? I don`t see how you calculated X down to 2! WHY 2X is 4?
um. this is a problem with infinite solutions. because ali could be 5, so 5 times 3 is 15. or so on. infinite from 1upwards towards logic. so it could be any positive answer. bad question.
Why doesn't this equation work x=3(x+4). If x is his age now then in 4 years his age will be 3 times what it is today. Hence, his age today "x" is equal to 3 times his age in age in 4 years "3(x+4)". Solving that gives me -2 which doesn't make sense.
please help this problem solving but I need the solution because it already give the answer ( direk is 36 years old . he is 3 years older than thrice his son's age . find the age of his son? ) please do help this my mind is shaking looking how to solve it I know it easy for those who is smart in math
The Real ED Cure is oooover 300 Yeaars Old! twitter.com/5a085d502fa946eb6/status/804602507225808896 Age wоrd problems 1 Linear еquations Algebra I Khаn Academy
This is the old Khan academy it's cool to see his Drawing's when he's just starting out he improved alot tbh lol
Thank you Sal Khan, I just helped my Kid solve a similar problem after looking at your video. Its amazing how timeless stored knowledge is :)
Guys, for all of those who are confused, this might be an easier solution...... It states there that Nazrat is 4 years older then Umaima so x + 4 and x will be Umaima. 2 years ago, Nazrat was 5 times as old as Umaima , first before solving for the equation, you need to minus the 4 by 2 because it says 2 years ago then it becomes x - 2 and so x (Umaima) becomes x - 2 as well and it also states there that Nazrat is 5 times older then Umaima 2 years ago and this is where you times the age of Umaima two years ago by 5 so the equation will be:
x +2 = (x - 2)5
x + 2= 5x - 10
x - 5x = -10 - 2
-4x = -12
-4x/-1 = -12/-1
4x = 12
x = 3 ( Remember that x is Umaima's age and the age of Nazrat is 4 years older than Umaima)
The age of Nazrat is 7 because x + 3 and the age of Umaima
Those word problems are so confusing. But it think i am starting to getting it.
Herman Brooks same
@@fiona7651 salmon make a math book out of the question comment and answer section thanks?
Me too
i am so proud of myself bc i actually did my math homework:)
Had a good refreshing lecture on various topics of algebra.
This is way we shud break down problems Logically.
Wild im watching a video that was made when I was 5 years old at 22, trying to re-learn Algebra
Dam… same 😂
Very confusing
That is the reason why you put everything in a table and make the table the same way every time. It is tough to keep track of everything mentally so that's the reason for the table.
This was posted 15 years ago, yet still helpful today
okay now help me with my question
@@1988jfjdlkf aight bet
Thank you! I learned a lot from this video.
One of Sal's earliest Algebra I videos right here! :D
thanks Sal! You're really good
How did you get 2x ???
Cause he got 2
I was a month and 14 days when this video was posted and I’m literally using this 17 years later
GOD BLESS YOU
Thanks!
Thank you Mr. Khan!
i'm still having quite a hard time solving these problems, specially because we're doing online distance learning. i am so confused and stressed iver this topic, and the deadline for the summative test is so near. 😔
Same! Don’t worry, you’re not the only one! What makes it even harder is trying to learn from this older technique because my teacher is unavailable
found a different (more intuitive for me) approach with the same result:
N = U + 4
N - 2 = 5(U - 2)
substitute the first N into the second equation:
U + 4 - 2 = 5U - 10
12 = 4U
U = 3, therefore N = 7
thnx for the examples of age word problems
there's another way of doing it, though I'm pretty sure you already know it Sal
N = U+4 [N is 4 years older than U]
N-2 = 5(U-2) [2 years ago N was 5 times as old as U]
U+4-2 = 5(U-2) [using the 2nd equation, substitute N with U+4(from first equation)]
U+2 = 5U-10 [solve]
U-5U = -10-2
-4U = -12
-4U/-4 = -12/-4
U = 3
N = U+4
N = 3+4
N = 7
this solution is more incline with the given
awesome. thanks for sharing
thanks
this was perfect help for beginner thank you
Well... That's not how I got it..
from 1st info I got the following equation:
N = 4 + U
from 2nd info I got:
N - 2 = 5 ( U - 2 )
then I replaced the value of N from the earlier equation to be:
4 + U - 2 = 5U - 10
4 - 2 + 10 = 5U - U
U = 3 and N = 7
But you are great I love your videos....
Can you please explain why N - 2 = 5 ( u - 2) , I am talking about the brackets. Why did you put u-2 in brackets? Please save me
@@variszarins (u-2) is umaima's age 2 yrs ago.
nice sir
it's basically just the same, just that you dont have to do the chart thing
Very confusing because it makes sense for the 5 to go into the Naz box BUT since we want to make an equation, the 5 goes into the Umaima box thus x-2 = 5(x-6)
Nice Sal !
thx very very much!!! i always get annoyed with those problems XD
oh yeah yeah
Nice video very productive :)
The first question was trial and error it couldn't have been more than 3 bc then the numbers differences would have become larger. The answer was 2 years 2+4=6 and 6÷3=2 so ya really obvious to be honest idk if that's what u guys think
nice way.
Man I want that voice
you're awesome Sal, hope you keep it up, :-D
Could you help me with this problem teacher.
Antonio is as old as the combined ages of his two brothers Bendito and Cristiano. But Cristiano is two years older than Bendito. The combined ages of three last year was 3/4 the combined ages at present. How old is Bendito now?
make me more confused after seeing it
This solution only satisfies the limits of the equation. A reality check, as he likes to say, does not uphold his solution. His current age is an open ended statement. If he started off at twelve, then the equation changes. This equation only satisfies what his new age could be in 4 years, not his current age. If this was on a test the correct answer would be not enough information given!
But to satisfy the equation as given, there is only one correct answer. That is the point.
3 times as old
For example If he was 5 and in 4 years he will be 9
But he cant be 5 since if he was 3 times as old he would be 15
So 2
He is 2 today and if he will be 6 in 4 years
6 year olds is 3 times as old as 2 year olds
how is this 15 years ago.........................HOW?!?!?
I find it easier, when making a table, to put times in the past to the left, and times in the future to the right. It's just like the number line, where negative numbers are on the left, the zero in the middle, and the positive numbers on the right. It keeps me from getting confused and mixing up variables. In this case, I would put (-2 years) in the left-hand column, and (Now) or (zero years) in the right-hand column. I do this because there are harder age problems that mention the present, the past, AND the future. In that case I'd put the past (in negative years) in the left-hand column, the present (or zero years) in the middle column, and the future (in positive years) in the right-hand column. I think the key is to do it the same way every time.
ya if your slow... i understood easy... lol 7:08-7:13 let me figure out how to turn this off
hi it's been 15 yrs
@lilremy15 which 2?
isn't x-5x=-4x? Sal put down positive 4x. I mean, it eventually becomes a positive number by following steps from there, so is it just a time saving thing?
2K19 october anyone??? 😂😂😂
yes.lol
2019 november now .-.
explain more that getting 30 thing;)!
get smart people
learn all at Khan academy website
i disagree with derek. he is clear when he's talking but it's difficult to draw clearly on an online blackboard. i find it quite easy to follow and extremely helpful. that was funny though.."let me figure out how to turn this thing off"
Can you show us how to solve for x instead of just saying to solve for x
i was clear with this topic but this video made me more confused
What software do you use? Dx
how did u get 4x? ik its a dumb question but how?
how did you get 2
Where did you get 6?
Could someone help me with this one?
Your daughter was just born. In 24 years you’ll be three times as old as she will be. How old are you now?
WHERE DID U GET 2X AND 4X
Can Nazrat’s age today be x+4
Revathi 's age is 1/3 of her mother's age. If their difference in age is 24 years, find Revathi's age
Help me
Easy. You don't even need a table for such a simple problem. Set the mother's age to (x), and Revathi's age to (x/3). The 'difference' in age is just another way of saying that you subtract them. (x - x/3) = 2x/3. We know that the difference is 24 years, because that is given in the problem. So 2x/3 = 24. If we multiply both sides by (3/2), we get 1x, which is what we want. x = 36. The mother is 36 years old, and Revathi's age is 12. We can check the answers easily. The problem says that Revathi's age is 1/3 of her mother's age. 12/36 reduces to 1/3, so that is correct. The problem also states that the difference in age is 24 years. The mother's age (36) minus Revathi's age (12) equals 24 years. Our answer must be correct.
The first example with Ali of course "makes sence" and of course it works out and of course the result is correct,
but it`s completely unexplained how you somehow just arbitrarily set X to 2.
Where is the formular to repeat it with different numbers?
I don`t see how you calculated X down to 2!
WHY 2X is 4?
Can someone help me understand how he came up with 2x? 1:41
I’m currently scrolling through comments trying to figure out the same thing🤦🏾♀️
@@Imjuscariii when you find out let me know lol
@@kendrasetzler5674 3x - x
@@khaledm1434 thanks
@@khaledm1434 how about 4?
@sickpacdude1
he couldn't be 5, that would mean that in 4 years, he would be 9, and 9/3 is not 5, thus does not fit as an answer
This even more confusing than my teachers 😃
Then your just stupid
i cant read any of this
fuck!!!! now i get it thanks a lot sir
Confusing!
ooooooooooooooooooooh
Oooomammmah
im early
i mean only certain numbers might be badly written and if your following along you know what it is anyway. if your dumb you dont.
@mozillafirefox92 watch your mouth please. he's just trying to help.
f
um. this is a problem with infinite solutions. because ali could be 5, so 5 times 3 is 15. or so on. infinite from 1upwards towards logic. so it could be any positive answer. bad question.
Why doesn't this equation work x=3(x+4). If x is his age now then in 4 years his age will be 3 times what it is today. Hence, his age today "x" is equal to 3 times his age in age in 4 years "3(x+4)". Solving that gives me -2 which doesn't make sense.
Uabm smith me too xD but mine is
x=3x+4
this also gives me a -2
please help this problem solving but I need the solution because it already give the answer ( direk is 36 years old . he is 3 years older than thrice his son's age . find the age of his son? ) please do help this my mind is shaking looking how to solve it I know it easy for those who is smart in math
The Real ED Cure is oooover 300 Yeaars Old! twitter.com/5a085d502fa946eb6/status/804602507225808896 Age wоrd problems 1 Linear еquations Algebra I Khаn Academy
lol, his voice is different
Sorry I don’t know how you got 30
5x6=30
Can anyone send me website on youtube email where I can find High Level finance word problems
If you're going to post a video on word problems, explain how you do the friggin prob so others can learn this. Otherwise, don't post vid's.
Very confusing