Question

A pipe can fill a cistern in 8hours and another can empty the cistern in 13hours how long will they take to fill the cistern if both the taps are open

Answer 1

Answer:

A ----------> 8hour

B ----------> -13hour

Total work =L.C.M of 8&13= 104 unit

A's 1 day work =13 unit

B's 1 day work =-8 unit

(A+B)'s 1 day work =13+(-8)=13-8=5 unit

Then A+B can complete 104 unit in=104/5=20 whole4/5 day.