Question

A can do a piece of work in 20 days and B in 15 days .They worked together on it for 6 days and then, A left . In how many days will B finish the remaining work ? 

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Answer 1

Step-by-step explanation:

Given A can do the work in 20 days and B can do it 15 days.

Then work done by A in one day =

$\frac{1}{20}$

And, work by B in one day =

$\frac{1}{15}$

Then, the work done by A & B in one dday =

$\frac{1}{20 } + \frac{1}{15} = \frac{7}{60}$

A & B done 6 days together then work done in A & B in 6 days =

$\frac{7}{60} \times 6 = \frac{7}{10}$

Then friction of work left=

$1 - \frac{7}{10} = \frac{3}{10}$

Then B can do

$\frac{3}{10} work = \frac{3}{10} \times \frac{15}{1} = \frac{9}{2 }$

$= 4 \frac{1}{2} days$

hope it helps you......★