Q9 of 28 Page 11

A, B and C can reap a field in days; B, C and D in 14 days; C, D and A in 18 days; D, A and B in 21 days. In what time can A, B, C and D together reap it?

Given,


A, B and C can reap the field in = 15 days


B, C and D can reap it in = 14 days


C, D and A can reap it in = 18 days


D, A and B can reap it in = 21 days


So,


A, B and C’s 1 day work =


B, C and D’s 1 day work =


C, D and A’s 1 day work =


D, A and B’s 1 day work =


Now, adding up,


3[A+B+C+D] =


A+B+C+D =


Thus A, B, C, D can finish the work in = days.


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