Question

Three men a b c can complete a work in 10 ; 15; 30 days respectively. a and b work together for 3 days then a leaves and c joins in how many days can b and c finish the remaining work

Answer 1

Hey.

Here is the answer.

As a can complete 1 work in 10 days

so, in 1 day a can do 1/10 of work

similarly in 1 day b can do 1/15 of work and

c can do 1/30 of work

Now, a and b work for 3 days then a leaves

so, work done together by a and b in 3 days

= 3/10 + 3/15 = (9+6)/30 =1/2 work

So, remaining work is 1 - 1/2 = 1/2 work

Now b and c completes the work ,

lets say in X days

so, work done in x days by b and c

= x/15 + x/30 = (2x+x)/30 = x/10 work

As work is complete

so, x/10 = 1/2

or, x = 10×1/2 = 5

Hence, in 5 more days b and c can finish the remaining work.

Thanks.