Applications of Rational Expressions (Work Rate Problems, Motion Problems)
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- Опубликовано: 11 сен 2024
- www.greenemath....
/ mathematicsbyjgreene
In this lesson, we review how to solve work rate word problems, otherwise known as rate of work problems. These problems deal with the speed at which a job can be completed by two or more people given their individual rates of work. Additionally, we will look at solving motion word problems that deal with rational equations.
Mr. Greene, you are an awesome teacher. I learn tons from you. Thanks a million.
You are very welcome!
IM SO GLAD THERE'S A VIDEO LECTURE FOR THIS, I THOUGHT I WAS FALLING BEHIND OUR LESSONS
Glad the lesson is helpful!
you explain the concepts very well! Thank you!
You're very welcome! Good luck with your studies :)
How did you know automatically that 14 was a common factor of 98 AND 210?
What's the time marker for your question?
@@Greenemath 7:36
I'm struggling with a motion problem. I'm given the distance, but the rate and the time are both variables. The distance is 120 miles. Car A travels that distance 36 minutes quicker and travels 10mph faster than Car B. I need to find the speed of Car B.
I just can't figure out how to lay out the problem. I thought 120/rt=120/(r+10)(t-.6) would get me there but the formula just seems wrong.
I'm coming back into algebra to help tutor a friend's child who is struggling. I've spent 2+ hours on this one problem and I'm worried I won't be able to be as helpful as I'd hoped.
The distance can't be 120mph, that's a rate of speed. I would assume you mean the distance is 120 miles?
If you solve for time, the distance formula becomes:
t = d/r
In each case, the distance is 120 miles.
t = 120 / r
So the idea is to let a variable like x represent the speed of let's say car A and then car B can be based on that decision.
let x = speed in mph of car A
Then x - 10 = speed in mph of car B
Car A:
t = 120 / x
Car B:
t = 120 / (x - 10)
From here, think about what you could do to get an equation. How can we set the times equal to each other?
25:18 the question problem already gave us total time done together and now is asking us to find each of them separately. So I thought we will subtract oppositive of adding like the previous problem where we actually had to find total time together
Just follow the steps given in the tutorial. Here is a written lesson, it might be easier to follow.
greenemath.com/College_Algebra/69/Rational-Equations-Word-ProblemsLesson.html
Hi Teacher Green,
Why are they called Rational Expression but not Rational Equations if they include the “=“ sign?
The correct last name is Greene, with an "e" at the end.
A rational expression is the quotient of two polynomials, where the denominator is not zero. In some cases, this will be defined as an algebraic fraction.
A rational equation is an equation that contains rational expressions. The term applications of rational expressions, just means we are working on problems that involve rational expressions. This is how it is titled in every Algebra book.
Oh! I am so sorry for spelling your name wrong! @@Greenemath
8:54, why can't we just subtract -7x from both sides instead of 15x?
Type out your steps and I will take a look for you.
Thanks man, very well explained
Glad it helped!
Thx sooo much!
You are very welcome! 😎
@@Greenemath Thank you again i got a 98 on my test. (2 points were my fault i did a silly mistake)
@@sashreddy6248 I'm really glad to hear that! Keep up the good work! 😎