Ajay and Balu together can do a piece of work in 12 days. Balu and Charan together can do the same work in 16 days. After Ajay has been working at it for 5 days and Balu for 7 days, Charan finishes it in 13 days. In how many days will Charan alone be able to do the work? Options.
A) 16 days B) 24 days C) 36 days D) 48 days E) 58 days

Rationale: let the total work be 48 units . ajay and balu ’ s one day work = 48 / 12 = 4 units . balu and charan ’ s one day work = 48 / 16 = 3 units . ajay ’ s one day work = 4 - balu ’ s one day work . balu ’ s one day work = 3 - charan ’ s one day work . therefore , ajay ’ s one day work = 1 + charan ’ s one day work . also given , 5 x ajay ’ s one day work + 7 x balu ’ s one day work + 13 x charan ’ s one day work = 48 equating all the equations formed , we get charan ’ s one day work is 2 units . hence , charan can finish the whole work in 48 / 2 = 24 days . answer : b
Answer: B