Answer-Pipe ‘A’ and pipe ‘B’, together can fill 20% of a tank in 7 hours while pipe...

Time taken by pipe lsquoArsquo and pipe lsquoBrsquo, together to fill the tank 70.20 35 hours Let the total capacity of tank 1260 units Efficiency of pipe A B 126035 36 unitshour Efficiency of pipe lsquoCrsquo 126036 35 unitshour Tank filled by pipe A B in 31 hours 31 times 36 1116 units Time taken by all three pipes to fill the remaining tank 1260 ndash 111636 ndash 35 144 hrs Total time taken 144 31 175 hours

Question

Pipe ‘A’ and pipe ‘B’,

together can fill 20% of a tank in 7 hours while pipe ‘C’ takes 36 hours to empty it. Pipe ‘A’ and pipe ‘B’ were opened together. After 31 hours, pipe ‘C’ is also opened. Find the total time taken to fill the empty tank this way.

A 160 hours

B 175 hours

C 150 hours

D 145 hours