Question

WORD PROBLEM

A tap has 2 taps. When running alone one tap can fill the tank in 20 minutes while the second tap can fill the tank in 60 minutes. How long does it take to fill the tank if both the taps are running together?

Answer 1

time taken by first tap to fill= 20 min--- i
time taken by sec tap to fill = 60 min --- ii

thus in one min amount filled by first tap = 1/20 (from i )
thus in one min amount filled by sec tap = 1/60 (from ii )
thus in min when both of them are open they together fill = 1/20 + 1/60
= 2/30
= 1/15
in 1 min = 1/15 part filled
so in 15 minutes = 15*(1/15) filled = full part filled
thus time taken to completely fill the tank is 15 minutes.