# A does 20% less work than B. If A can finish a piece of work in 7(1/2) hours then B can finish it in  A. 5 hours B. 5 (1/2) hours

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A does 20% less work than B. If A can finish a piece of work in 7(1/2) hours then B can finish it in

A. 5 hours

B. $5\frac{1}{2}$ hours

C. 6 hours

D. $6\frac{1}{2}$ hours

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Number of hours taken by A to finish the work = $7\frac{1}{2}$ hours = $\frac{15}{2}$ hours

Work done by A in one hour : $\frac{2}{15}$

Let number of hours taken by B to finish the work : $\frac{1}{x}$

A can work 20% less than B that is $\frac{20}{100}=\frac{4}{5}$ times of B’s work.

Here , $\frac{4}{5}:1=\frac{2}{15}:\frac{1}{x}$

$\frac{4}{5}=\frac{2x}{15}$

x = $\frac{15\,\times\,4}{5\,\times\,2}$ = 6 hours.