A is thrice as good a workman as B and therefore is able to finish a job in 40 days less than B.

A is thrice as good a workman as B and therefore is able to finish a job in 40 days less than B. Working together they can do it in: (a) 14 days (b) 13 days (c) 20 days (d) 15 days

Correct option (d) 15 days Explanation:  According to question,

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