simple math from OG11

[Maggie12]

Hi

can anyone solve the problem

A rainstorm increased the amount of water stored in State J reservoirs from 124 billion gallons to 138 billion gallons. If the storm increase the amount of water in the reservoirs to 82 percent of total capacity, approx how many billion gallons of water were the reservoirs short of total capacity prior to the storm?

A 9

B 14

C 25

D 30

E 44

[aroon7]

OA is E

138 = (82/100)(Total capacity)
Ans is Total capacity - 124

this will be approx. 44

This is an OG-11 problem: Page 152, Q# 6

please let me know if you still have problems

[480ocean]

As illustrated in the previous post, the formula you can use is: Part = % * Whole

138 = 82% * Whole
(Whole means the total amount of water at 100% full - which means total capacity, which is unknown)
138 = .82 * Whole
Divide both sides by .82
168 = Whole

Then,
168 - 124 = 44 billion gallons short of total capacity prior to the storm.

Hope this helps too!