Tap A can fill up an empty tank in 3 hours.Tap B can fill up the same empty tank in 4 hours.Tap C can fill up the same empty tank in 6 hours.How many hours will it take to fill up the empty tank if all the taps are turned on at the same time?

Guest Jun 24, 2014

#1**+5 **

If the volume of the tank is, say, V litres, then

A fills it at a rate of V/3 litres/hour

B fills it at a rate of V/4 litres/hour

C fills it at a rate of V/6 litres/hour

So A+B+C would fill it at a rate of V/3 + V/4 + V/6 = 3V/4 litres/hour

Time taken = V/(3V/4) = 4/3 hours or 1hour 20 minutes.

Alan
Jun 24, 2014