Question

pipe A can fill a tank in 4 hours and pipe can fill it in 6 hours. if they are opend at alternate hours and if pipe A is opened first, in how many hours will the tank be filled​

Answer 1

lcm (4,6)= 12

efficiency 3:2

total efficny 5

12/5= 2 (as it is alternate hours take the bouble 4)

then started with 3 efficiency pipe so 4 2/3 hrs or 4 hr 40 min