HOURS⇒ Tap A’s 1 hour work = 1 / 40 ----1⇒ Tap B can fill in 48 hours⇒ Tap B’s 1 hour work = 1 / 48 ----2⇒ Tap C can fill in 60 hours⇒ Tap C’s 1 hour work = 1 / 60 ----3⇒ Now Tap A, B and C’s 1 hours work = 1/40 + 1/48 + 1/60⇒ Tap A, B and C’s 1 hours work = (6 + 5 + 4)/240⇒ Tap A, B and C’s 1 hours’ work = 1/16∴ A, B and C can fill the tank TOGETHER in 16 hours