# A man has three sons. First and second son can complete a work in 24 d

| A man has three sons. First and second son can complete a work in 24 days and 36 days respectively. The man himself can complete the same work in 36/11 days. If the man does twice the work in the same time his three sons complete the whole work together, then in how many days his third son will complete the work alone?

A. 10 days

B. 12 days

C. 15 days

D. 8 days

### Right Answer is: B

#### SOLUTION

Let the total work = LCM(24,36) = 72 units

Efficiency of first son = 3 units

Efficiency of second son = 2 units

Efficiency of man himself = 72/(36/11) = 22 units

According to the question,

Efficiency of man = Twice the sum of efficiencies of his sons

22 = 2(Efficiency of first son + Efficiency of second son + Efficiency of third son)

11 = 2 + 3 + Efficiency of third son

Efficiency of third son = 11-5 = 6 units

Time taken by third son to complete the work = 72/6 = 12 days

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A man has three sons. First and second son can complete a work in 24 d