Question

.A and B can do a piece of work in 12 days, B
and C in 15 days, C and A in 20 days. In how
many days will they finish it together .​

Answer 1

Answer:

A + B can do the work in 12 days.

In a single day A+B will do 1/12 th portion of the work.

B+C can do the work in 15 days.

In a single day B+C will do 1/15 th portion of the work.

A + C can do the work in 20 days.

In a single day A+C will do 1/20 th portion of the work.

In a day (A+B)+(A+C)+(C+A) will do=(1/12)+(1/15)+(1/20) portion of the work.

2(A+B+C)=(1/12)+(1/15)+(1/20)=1/5 portion of the work.

Then, (A+B+C) will do =1/10 portion of the work in a day

A+B+C will complete the work in 10 days.

C can finish the portion of the work in a single day = Single day work of (A+B+C)-(A+B)=(1/10)-(1/12)=1/60

So C alone can finish the work in just 60 days.

B can finish the portion of the work in a single day = Single day work of (A+B+C)-(A+C)=(1/10)-(1/20)=1/20

So B alone can finish the work in just 20 days.

A can finish the portion of the work in a single day = Single day work of (A+B+C)-(B+C)=(1/10)-(1/15)=1/30

So A alone can finish the work in just 30 days.

Hope this helps.

Mark as BRAINTIST .

Answer 2

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