Jars ratio

[GmatKiss]

Equal amount of water is poured into two emply jars of diff. capacities, which make of jar 1/4 and teh other 1/3 full. If water in the jar with the lesser capacity if pour into the one with the greater, what fraction of the large will be filled?

1/7
2/7
1/2
7/12
2/3

[GMATGuruNY]

Equal amount of water is poured into two emply jars of diff. capacities, which make of jar 1/4 and teh other 1/3 full. If water in the jar with the lesser capacity if pour into the one with the greater, what fraction of the large will be filled?

1/7
2/7
1/2
7/12
2/3

The larger jar is 1/4 full.
The smaller jar contains the same amount of water.
Thus, when the water from the smaller jar is poured into the larger jar, the volume in the larger jar will double:
2 * (1/4 full) = 1/2 full.

The correct answer is C.

[bblast]

I faced this in GMAT prep II. I solved it 2 ways to be sure . One is Mitch's method.
Another :
Or you can take LCM of 4 and 3 = 12.

let larger jar = 12 litres
let smaller jar = 9 litres

If we add 3-3 litres to both;
larger will be full to 1/4(3/12) capacity and smaller to 1/3(3/9).

If all 6 litres are in larger jar its full upto 6/12 = 1/2 capacity.