Question

A alone can do piece of work in 12days and B can do same work in 15days. A alone do work for 4 days. Then A and B can do together to finish the work?

Answer 1

.

A takes 12 days

B takes 15 days

.

A and B = (12 x 15) / ( 12 + 15) = 6 2/3 days

.

Answer: They will take 6 2/3 days to finish the work.

.

.

A and B =

Answer 2

Given,

A= 12 Days

B= 15 Days

By using chocolate concept of aptitude,

LCM(12,15)= 60 Chocolates (total work)

One day work of,

A =60÷12= 5 chocolates/day

B =60÷15= 4 chocolates/day

One day work of,

A and B together= 5+4

= 9 chocolates/day

w.k.t, Total No of Days

= (Total work) ÷ (Efficiency of A and B)

= 60 ÷ 9

= 6.67 days (exactly)

= 7 days (approximately)

So, A and B together can do a work in 7 days