Question

A and B can do a job in 60/7 hrs, B and C can do a job in 12 hrs & A and C can do a job in 10 hrs. How long will each of them take to do the job?​

Answer 1

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Let the work done by A, B and C in one day be A, B and C respectively.

A and B can finish a job in 30 days.

So A+B = 1/30

B and C can do the same job in 40 days.

So B+C = 1/40

C and A do it in 60 days.

So C+A = 1/60

Now, if we add all the above mentioned sets together, we get the work done by all of them together in 2 days. Lets check that…

(A+B)+(B+C)+(C+A) = 1/30+1/40+1/60

2A+2B+2C = (4+3+2)/120

2(A+B+C) = 9/120

2(A+B+C) = 3/40

As per above calculations, the work done by all of them together in 2 days = 3/40

So the work done by all of them together in 1 days = 3/40÷2

A+B+C = 3/80

Number of days taken by them to complete the work = 1÷3/80

= 1*80/3

= 26 2/3 days or 26.67 days or 27 days approx.