thx for the video, another way of looking at the last problem is that, subtract two adjacent numbers for example 1/2 - 1/4 = 1/4. Do this for the first few terms, you will notice that all the negative numbers disappear, only positive numbers added together starting with 1/4, the quarter will only grow higher. Hence, quantity A must be larger, this way leads to the same conclusion as using a graph, but I feel it is easier to realize because it is more consistent with the way we solved previous problems as we rarely would use a graph to solve a GRE problem.
Writing 1/8 above 1/4 was just a mistake. It should read 3/8 instead of 1/8. The point there was that we added 1/8 to 1/4 as we moved from the second to the third term. There are probably several other ways of looking at this problem. That's one of the great things about these standardized tests: they reward flexibility. Please let us know if you come up with another way of looking at this question as we're always on the lookout for new ways to solve problems. I hope that helps!
This is where you have to be careful with the notation. In the solution, we showed that P(k) = 3^(4-k). This means that P(60) = 3^(4-60) = 3^(-56), but neither Quantity A or Quantity B is equal to 3^(-56) so we can't say it's clear without solving that both quantities are equal to P(60). Without working out how the sequence works and doing some algebra, I wouldn't want to assume that both quantities end up at the same term. It isn't clear at the start of the question that they will end up this way. After we do some work with the exponents, we can show that both Quantity A and Quantity B are equal to 3^(-60) which is the 64th term or P(64). Once we hit this stage, it's definitely sufficient to say the answer to this question is (C). I hope that helps!
Hi Adithya, In this question, quantity A is the *sum* of the first ten terms of the sequence, which would be 1/2 - 1/4 + 1/8 - 1/16 + 1/32 - 1/64 + 1/128 - 1/256 + 1/512 - 1/1024. If you calculate this, the value will be greater than 1/4, so the answer to this question will be (A). The method I used in the video is one way of reasoning toward the answer without doing the full calculation. I'd want to avoid doing the full summation since doing this would use up far too much time. I hope that helps!
Q3 it's much faster for me to just keep adding 5 on calculator until 200 and I got my answer. Remembering those formulas will just confuse me, but that's just me.
thx for the video, another way of looking at the last problem is that, subtract two adjacent numbers for example 1/2 - 1/4 = 1/4. Do this for the first few terms, you will notice that all the negative numbers disappear, only positive numbers added together starting with 1/4, the quarter will only grow higher. Hence, quantity A must be larger, this way leads to the same conclusion as using a graph, but I feel it is easier to realize because it is more consistent with the way we solved previous problems as we rarely would use a graph to solve a GRE problem.
This is a great way of looking at this question! Thank you for sharing it.
If we can place somethong every meter, on a 3 m road we can place 3/1 +1 thing, because we can place the thing on the 0 or close to it
any other way to look at the last problem ? In the last question why did u write 1/8 above 1/4 , as 1/8 is less than 1/4
Writing 1/8 above 1/4 was just a mistake. It should read 3/8 instead of 1/8. The point there was that we added 1/8 to 1/4 as we moved from the second to the third term.
There are probably several other ways of looking at this problem. That's one of the great things about these standardized tests: they reward flexibility. Please let us know if you come up with another way of looking at this question as we're always on the lookout for new ways to solve problems.
I hope that helps!
For the find the pattern question, without solving it is clear Quantity A and B are equal to P^60 is this sufficient to arrive at answer C?
This is where you have to be careful with the notation. In the solution, we showed that P(k) = 3^(4-k). This means that P(60) = 3^(4-60) = 3^(-56), but neither Quantity A or Quantity B is equal to 3^(-56) so we can't say it's clear without solving that both quantities are equal to P(60).
Without working out how the sequence works and doing some algebra, I wouldn't want to assume that both quantities end up at the same term. It isn't clear at the start of the question that they will end up this way. After we do some work with the exponents, we can show that both Quantity A and Quantity B are equal to 3^(-60) which is the 64th term or P(64). Once we hit this stage, it's definitely sufficient to say the answer to this question is (C).
I hope that helps!
For the last question, shouldn't it be (B), 1/4 > Anything above 1/4 i.e (1/5, 1/6 etc)?
Hi Adithya,
In this question, quantity A is the *sum* of the first ten terms of the sequence, which would be 1/2 - 1/4 + 1/8 - 1/16 + 1/32 - 1/64 + 1/128 - 1/256 + 1/512 - 1/1024. If you calculate this, the value will be greater than 1/4, so the answer to this question will be (A).
The method I used in the video is one way of reasoning toward the answer without doing the full calculation. I'd want to avoid doing the full summation since doing this would use up far too much time.
I hope that helps!
Q3 it's much faster for me to just keep adding 5 on calculator until 200 and I got my answer. Remembering those formulas will just confuse me, but that's just me.