Lesson: Finding x Percent of y

Question link: http://greprepclub.com/forum/for-the-seven-ailments-what-is-the-median-o...

Part of your approach is correct, but we need not ADD all of percents. To find the median, we list the values in ascending order, and the median is the middlemost number.

The percentages in group 2, listed in ASCENDING order are: {3%, 4%, 5%, 6%, 10%, 11%, 21%}

So, the MEDIAN value is 6%

6% of 400 = (0.06)(400) = 24

Great question.

The quick answer is: No, if the percent increase from X to Y is k%, then the percent decrease from Y to X is not k%.

Here's a quick example:

If we go up from 50 to 100, the percent increase is 100%

However, if we go down from 100 to 50, the percent decrease is 50%

Likewise, if we go up from 40 to 45, the percent increase = (100)(45 - 40)/40 = 500/40 = 12.5%

However, if we go down from 45 to 40, the percent increase = (100)(45 - 40)/45 = 500/45 ≈ 11.11%

Cheers,
Brent

Question link: https://greprepclub.com/forum/bella-s-baubles-wants-to-sell-a-necklace-f...

If an item is 60% off (i.e., a 60% discount), then you PAY 40% of the original price.
That is: SALE price = 40% of the ORIGINAL price.

For example, if $100 = the original price, then the sale price = 0.4($100) = $40

So, in this question, the sale price = 0.4x (not 0.6x as you have in your solution).
We write: 0.4x = 179.95

Does that help?

Cheers,
Brent

Let W = number of wizards in magic club

GIVEN: There are 20% more goblins than wizards
So, the number of goblins = (number of wizards ) + (20% more)
= W + (20% of W)
= W + 0.2W
= 1.2W

GIVEN: There are 120 goblins in magic club.
So, we can write: 1.2W = 120
Divide both sides by 1.2 to get: W = 100

Answer: 100

ASIDE:
So, increasing a value by 20% is the same as multiplying that value by 1.2
Similarly, increasing a value by 30% is the same as multiplying that value by 1.3
And increasing a value by 78% is the same as multiplying that value by 1.78
etc

Does that help?

Cheers,
Brent

Hi Sri,

Here's the video on percent increase and decrease: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1083

The other three concepts fall under the general heading of percents, which can be found in the above video, as well as in these two videos:
- https://www.greenlighttestprep.com/module/gre-arithmetic/video/1077
- https://www.greenlighttestprep.com/module/gre-arithmetic/video/1078

Cheers,
Brent