We are dealing in %, so lets pick a number to make life easier.
Enrollment in 1990 = 100
Enrollment in 1980 = 83
So, what percent does 83 need to be increased by to give 100 ?
83 + (x/100) * 83 = 100
solve to get x = 20 as the closest value.
So, (C) I think
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Percentages
Source: Beat The GMAT — Problem Solving |
You should immediately recognize that 83 1/3 % = 0.833333 = 5/6.
This is one of the common fractions you need to know.
So, the change was from 5/6 x to x.
The change was 1/6 x.
Since the original amount was 5/6 x, the % increase is:
(1/6)x / [(5/6)x] =
(1/6) / (5/6) =
(1/6) * (6/5) = 6/30 = 1/5 = 20%
This is one of the common fractions you need to know.
So, the change was from 5/6 x to x.
The change was 1/6 x.
Since the original amount was 5/6 x, the % increase is:
(1/6)x / [(5/6)x] =
(1/6) / (5/6) =
(1/6) * (6/5) = 6/30 = 1/5 = 20%
Greg Michnikov, Founder of GMAT Boost
GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.
Also, check out the most useful GMAT Math blog on the internet here.
GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.
Also, check out the most useful GMAT Math blog on the internet here.
Thanks a lot GMAT Boost, but could you pls tell what are the other percentage fractions one need to learn.
Thanks for your help.
Thanks for your help.
Sorry for the delay, I decided to answer in the form of a blog post so that I could refer to it in the future:Thanks a lot GMAT Boost, but could you pls tell what are the other percentage fractions one need to learn.
https://blog.gmatboost.com/2011/08/15/me ... rcentages/
Let me know if you have any questions.
Greg Michnikov, Founder of GMAT Boost
GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.
Also, check out the most useful GMAT Math blog on the internet here.
GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less.
It's a total of 20+ hours of expert instruction for an introductory price of just $10.
View sample questions and tips without signing up, or sign up now for full access.
Also, check out the most useful GMAT Math blog on the internet here.












