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

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Math Expert
Joined: 02 Sep 2009
Posts: 58417
A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Oct 2012, 01:53
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Difficulty:

15% (low)

Question Stats:

76% (01:02) correct 24% (01:19) wrong based on 1881 sessions

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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%

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Question: 58
Page: 160
Difficulty: 550

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Oct 2012, 01:53
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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.

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Oct 2012, 02:03
1
Bunuel wrote:
The Official Guide for GMAT® Review, 13th Edition - Quantitative Questions Project

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: 600

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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%

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

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Oct 2012, 02:45
1
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%
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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09 Oct 2012, 22:10
1
Water evaporated = 0.01 *20 ounce = 0.20 ounce
Original water = 10 ounce
Water evaporated as percentage = 0.20 *100/10 = 2%
Ans D.
Bunuel wrote:
The Official Guide for GMAT® Review, 13th Edition - Quantitative Questions Project

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: 600

GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition - Quantitative Questions Project

Each week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project:
2. Please vote for the best solutions by pressing Kudos button;
3. Please vote for the questions themselves by pressing Kudos button;
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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11 Oct 2012, 03:48
1
Before 10 onces

After 0.01 * 20 = 0.2

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

D wins
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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02 May 2013, 10:28
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.
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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10 Jul 2014, 01:16
1
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%

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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03 Jun 2016, 06:34
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Bunuel wrote:
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%

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%

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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03 Jun 2017, 01:51
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%
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Sep 2017, 03:41
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%
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Sep 2017, 05:02
Important formulae needed to solve this question is percent change = (original - actual / original) *100. Ans D wins

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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08 Sep 2017, 05:03
Shiv2016 wrote:
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%

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

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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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12 Jan 2018, 22:40
Bunuel niks18 amanvermagmat

Is this final step correct too:
What percent of the original amount of water evaporated during this period?
Quote:
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.

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%
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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12 Jan 2018, 23:34
1
Bunuel niks18 amanvermagmat

Is this final step correct too:
What percent of the original amount of water evaporated during this period?
Quote:
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.

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%

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%$$=\frac{50}{100}=0.5$$
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce  [#permalink]

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27 Jan 2019, 20:59
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Re: A glass was filled with 10 ounces of water, and 0.01 ounce   [#permalink] 27 Jan 2019, 20:59
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