water tank

[gmatnmein2010]

Working at a constant rate respectively, pumps X and Y took 48 hours to fill an empty water tank. What fraction of the water in a full tank came from pump X?

(1) working alone at its constant rate, pump X would have taken 80 minutes to fill tank with water

(2) working alone at its constant rate, pump y would have taken 120 minutes to fill up the tank

[thephoenix]

Working at a constant rate respectively, pumps X and Y took 48 hours to fill an empty water tank. What fraction of the water in a full tank came from pump X?

(1) working alone at its constant rate, pump X would have taken 80 minutes to fill tank with water

(2) working alone at its constant rate, pump y would have taken 120 minutes to fill up the tank

is it hrs or min.

IMO D

given x and y together take 48mins.
----->1/X + 1/Y = 1/48

stmnt1 - Pump X 80mins to fill the tank so in 48mins it will fill 48/80 * 100 = 60% of the tank. hence suff

stmnt2 - since Y takes 120mins
to fill tank then in 48mins it will fill 48/120 * 100 = 40%. the remaining 60% is filled by X. hence suff

so D

[shashank.ism]

Working at a constant rate respectively, pumps X and Y took 48 hours to fill an empty water tank. What fraction of the water in a full tank came from pump X?

(1) working alone at its constant rate, pump X would have taken 80 minutes to fill tank with water

(2) working alone at its constant rate, pump y would have taken 120 minutes to fill up the tank

I think there is some mistake in the question...If X can fill tank in 80 minutes
or Y can fill tank in 120 min.

How can both tak 48 hours to fill the tank...sth fishy .....gmatnmein2010 please chk the question from OS