Question

6 pipes fill a tank in 120 minutes, then 5 pipes will fill it in

(a) 100 min (b) 144 min

(c) 140 min (c) 108 min

Answer 1

Answer : (b)

No. of pipes 6 : 5

Time taken to 120 min : x min

fill the tank

Less pipes, more time

$\therefore$ By inverse proportion

6 : 5 : : x : 120

$x=\frac{6\times 120}{5}=144$

$\therefore$ Time taken = 144 minutes