Pipe &lsquoA&rsquo and pipe &lsquoB&rsquo, together can fill 20% of a tank in 7 hours while pipe

divTimetakenbypipelsquoArsquoandpipelsquoBrsquotogethertofillthetank702035hoursdivdivLetthetotalcapacityoftank1260unitsdivdivEfficiencyofpipeAB12603536unitshourdivdivEfficiencyofpipelsquoCrsquo12603635unitshourdivdivTankfilledbypipeABin31hours31times361116unitsdivdivTimetakenbyallthreepipestofilltheremainingtank1260ndash111636ndash35144hrsdivdivTotaltimetaken14431175hoursdiv

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