Question

A can do a piece of work in 4hrs A and B can do piece of work in 1.77 hrs ?how many hours does B need only?​

Answer 1

We know that,

Number of hours A required to do piece of work = 24 hours

Number of hour B required to do piece of work = 16 hours

Let us consider number of hours C required to do piece of work = x hours

Number of hours A,B and C together required to do piece of work = 8 hours

∴ We can calculate,

work done by A in 1 hour = 1/24

Work done by B in 1 hour = 1/16

Work done by C in 1 hour = 1/x

Work done by A, B and C together in a one hour = 1/8

Now, work done by A,B and C together in 1 hour= 1/24 + 1/16 +1/x = 5/48 + 1/x 5/48 + 1/x = 1/8 (5x+48)/48x = 1/8 40x + 384 = 48x 8x = 384 x = 384/8 = 48

∴ C can do the work in 48 hours.