BTGmoderatorDC wrote:A tank has 5 inlet pipes. Three pipes are narrow and two are wide. Each of the three narrow pipes works at 1/2 the rate of each of the wide pipes. All the pipes working together will take what fraction of time taken by the two wide pipes working together to fill the tank?
(A) 1/2
(B) 2/3
(C) 3/4
(D) 3/7
(E) 4/7
OA E
Source: Veritas Prep
Given all the 5 pipes are open, to fill the tank, say each of the three narrow pipes fills y liters; thus, each of the two wode pipes would fill 2y liters. So,
"¢ Three narrow pipes fill 3y liters and
"¢ Two wide pipes fill 4y liters
So, the capacity of the tank = 3y + 4y = 7y liters
Thus, all the pipes working together did 7y/4y = 7/4 of the work done by the two wide pipes working together to fill the tank. Since time and work are inverse;y proportional, all the pipes working together, will take 1/(7/4) = 4/7 of time taken by the two wide pipes working together to fill the tank.
The correct answer:
E
Hope this helps!
-Jay
_________________
Manhattan Review GMAT Prep
Locations:
GMAT Classes Munich |
GMAT Prep Courses Kuala Lumpur |
LSAT Prep Courses DC |
SAT Prep Classes Boston | and many more...
Schedule your free consultation with an experienced GMAT Prep Advisor!
Click here.
