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PS - water poured

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PS - water poured

by Xbond » Fri Sep 11, 2009 10:44 am
Hi there,

Could you give me your ELEGANT, QUICK, and EFFICIENT method to resolve (with these concepts and with finding the solution).


Equal amounts of water were poured into two empty jars of different capacities, which made one jar ¼ full
and the other jar 1/3 full. If the water in the jar with the lesser capacity is then poured into the jar with greater capacity, what fraction of the larger jar will be filled with water?

a)1/7
b)2/7
c)½
d)7/12
e)2/3
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by Nermal » Fri Sep 11, 2009 12:03 pm
I find picking numbers easiest on this question:

jar with capacity of 9 liters and
jar with capacity of 12 liters.

Pour 3 liters into each of them (smaller one: 3/9=1/3; bigger one: 3/12=1/4).
Now pour the 3 liters of the smaller jar into the bigger one and you get 6/12=1/2

Answer C (1/2)
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by Xbond » Sat Sep 12, 2009 9:24 am
many thks

OA is C
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Re: PS - water poured

by Ian Stewart » Sat Sep 12, 2009 11:59 am
Xbond wrote: Equal amounts of water were poured into two empty jars of different capacities, which made one jar ¼ full
and the other jar 1/3 full. If the water in the jar with the lesser capacity is then poured into the jar with greater capacity, what fraction of the larger jar will be filled with water?

a)1/7
b)2/7
c)½
d)7/12
e)2/3
The jar with lesser capacity is the one which is most full, so we pour the water from the jar which is 1/3 full into the jar which is 1/4 full. Since the amounts of water are equal, this will double the water in the 1/4 full jar, leaving us with a jar which is 1/2 full.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

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Re: PS - water poured

by sudi760mba » Wed Sep 16, 2009 2:50 am
Some of these questions are best with numbers picked.


Jar A: Capacity = 12 litres
A: 1/4 * 12 = 3 litres

Jar B: We need to use the same amount so we set x(capacity of B) to 3 litres.

1/3 * x = 3 litres
x = 9 litres
Jar B: 9 litres

3 litres + 3 litres = 6 litres
6/12 = 1/2
C
Xbond wrote:Hi there,

Could you give me your ELEGANT, QUICK, and EFFICIENT method to resolve (with these concepts and with finding the solution).


Equal amounts of water were poured into two empty jars of different capacities, which made one jar ¼ full
and the other jar 1/3 full. If the water in the jar with the lesser capacity is then poured into the jar with greater capacity, what fraction of the larger jar will be filled with water?

a)1/7
b)2/7
c)½
d)7/12
e)2/3
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by isaaczx » Tue Oct 06, 2009 11:20 pm
1/4 A = 1/3 B
A' = 1/4A + 1/3B
So A' = 1/4A + 1/4A = 1/2A
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by ikaplan » Mon Dec 19, 2011 11:05 am
Thanks
"Commitment is more than just wishing for the right conditions. Commitment is working with what you have."
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by LalaB » Mon Dec 19, 2011 12:10 pm
lets assume, that amount of water= 1

then-

1=1/3*C1 (C1=Capacity of jar 1) C=3

1=1/4*C2 C2=4

from above info, we can easily assume that jar 1 is with lesser capacity. so, we add the amount of water of jar 1 to the amount of water of jar 2.

now we have (1+1)/4 =1/2
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by pemdas » Mon Dec 19, 2011 12:28 pm
once more
x and y are two jars
x/4=y/3 and 4y=3x. It's evident y is less than x. Therefore, (y/3+x/4)/x will give us right proportion. We need to substitute and plug in y=3x/4 -> (3x/12+x/4)/x=6x/12x=1/2
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