Three pipes A, B and C working together can fill a tank in 6 hours. If A can fill it in 15 hours and B can fills it in 20 hours, then how much time will C take to fill the tank alone?
Answer & explanation
Correct answer: option 2
Efficiency of C = Eff. of (A + B + C) - Eff. of ( A + B )
= 10 - 7 = 3
C will fill it in → \(\frac{60}{3}\) = 20 hours.