A glass was filled with 10 ounces of water, and 0.01 ounce

Question

A glass was filled with 10 ounces of water, and 0.01 ounce of the water evaporated each day during a 20-day period. What percent of the original amount of water evaporated during this period?

(A) 0.002%
(B) 0.02%
(C) 0.2%
(D) 2%
(E) 20%

Practice Questions 
Question: 58
Page: 160
Difficulty: 550

Bunuel · Accepted Answer

SOLUTION

A glass was filled with 10 ounces of water, and 0.01 ounce of the water evaporated each day during a 20-day period. What percent of the original amount of water evaporated during this period?

(A) 0.002%
(B) 0.02%
(C) 0.2%
(D) 2%
(E) 20%

In 20 days 20*0.01=0.2 ounces of water evaporated, which is  \frac{0.2}{10}*100=2%  of the original amount of water.

Answer: D.

MacFauz · Answer

0.01 ounce evaporates each day for twenty days. So totally 0.01 x 20 = 0.2 ounces have evaporated
(0.2/10)*(100) = 2%
Answer is hence D

Although I'm having my doubts since I'm getting the answer to a 600 level question so easily

fameatop · Answer

Amount to water evaporated during 20 days = .01 * 20 = 0.2 ounce
percent of the original amount of water evaporated = .2 * 100/10 = 20/10 = 2% 
Answer D

Vips0000 · Answer

Water evaporated = 0.01 *20 ounce = 0.20 ounce
Original water = 10 ounce
Water evaporated as percentage = 0.20 *100/10 = 2%
Ans D.

Carcass · Answer

Before 10 onces

After 0.01 * 20 = 0.2

tranlsate x/100 of 10 = 0.20 -----> 2

D wins

feellikequitting · Answer

I'm tackling the problem head on with simple math, 10x.01=.10x20=2%

Can someone tell me why they would prefer using fractions opposed to multiplications, for this specific problem.

PareshGmat · Answer

In 10 ounces, 0.01 evaporates; so

in 100 ounces, 0.1 will evaporates in one day

So in 20 days, evaporation = 20 * 0.1 = 2%

Answer = E

JeffTargetTestPrep · Answer

We are given that 0.01 ounces of water evaporated EACH DAY. Furthermore, we know that this process happened over a 20-DAY PERIOD. To calculate the total amount of water that evaporated during this time frame we need to multiply 0.01 by 20. This gives us:

0.01 x 20 = 0.2 ounces

Finally, we are asked for “What percent” of the original amount of water evaporated during this period. To determine this percentage, we have to make sure we translate the expression correctly. We can translate it to:

(Amount Evaporated/Original Amount) x 100%

(0.2/10) x 100%

(2/100) x 100% = 2%

Answer D

AK92 · Answer

We have 10 ounce of water, every day for 20 days evaporates 0.01 ounce, yielding 20*0.01= 0.2 ounce for the whole 20 day period.
Now set up the percent relationship 0.2/10 *100= 2% 
Answer D!

Shiv2016 · Answer

Water that evaporated= 0.01*20 days= 0.2

a% of 10= 0.2
a= 0.2*100/10= 2%

If we were asked to find how much water is left:

(10-0.2)/10 * 100
= 98%

Adityagmatclub · Answer

Important formulae needed to solve this question is percent change = (original - actual / original) *100. Ans D wins

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Adityagmatclub · Answer

100-2=98 
Tell us about how much water is left

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adkikani · Answer

Bunuel   niks18   amanvermagmat

Is this final step correct too:
 What percent of the original amount of water evaporated during this period? 
 
This is same as:
0.2/ 10 
Now % means divide by 100, or we can multiply both numerator and denominator by 10:
2/100 or 2%

niks18 · Answer

Hi  adkikani

when you are asked to find percent you multiply by 100. for eg. 2 is what % of 4  = \frac{2}{4}*100=50 %

and when a % value is given then to convert it into simple number you divide by 100 for eg 50% =\frac{50}{100}=0.5

EMPOWERgmatRichC · Answer

Hi All,

We’re told that a 10 total ounces of water is evaporated at a rate of 0.01 ounces of water each day for 20 days. We’re asked what PERCENT of the water EVAPORATED during those 20 days.

You should notice that the 5 answers all involve percentages AND decimals (so this is a ‘decimal shift’ question). We’ll have to be really careful about how we approach our calculations, since if we make a little mistake, then we’ll choose one of the wrong answers and not even know it.

First, (0.01 ounces/day)(20 days) = .2 ounces of water evaporated

.2/10 = 2/100 = 2%

Final Answer:  D

GMAT Assassins aren’t born, they’re made,
Rich

totaltestprepNick · Answer

D https://www.youtube.com/watch?v=7vJnxvEM89E Nick Slavkovich, GMAT/GRE tutor with 20+ years of experience tutoring@totaltestprep.net

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