Discussion of Question with ID = 074 under Pipes-and-Cisterns

This is the discussion forum for this question. If you find any mistakes in the solution, or if you have a better solution, then this is the right place to discuss. A healthy discussion helps all of us, so you are requested to be polite and soft, even if you disagree with the views of others. The question and its current solution has also been given on this page.

Advertisement

Question

Two taps X, Y and Z can fill a tank in 18, 17 and 10 minutes respectively. All the taps are turned on at the same time. After how many minutes is the tank completely filled?

A

$4{109/164}$ mins.

B

$5{114/163}$ mins.

C

$3{103/166}$ mins.

D

$7{95/166}$ mins.

Soln.
Ans: a

Let the time be x mins. Then sum of works done by X, Y and Z = 1. $x/18 + x/17 + x/10 = 1$. Solving, we get x = $4{109/164}$. Or use the shortcut ${abc}/{ab + bc + ca}$. Another thing, instead of solving the entire calculation, you can keep an eye on the options to find the nearest answer.


Comments and Discussion