Question

A can do a piece of work in 15 days and B alone can do it in 10 days. B works at it for 5 days and then leaves. How much time will A take to complete the remaining work alone?

Answer 1

If B works at it for 5 days and leaves then A alone can finish the remaining work in 7.5 days. Then, ½ of the work will be done by A in = = 7.5 days

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Answer 2

If B works at it for 5 days and leaves then A alone can finish the remaining work in 7.5 days.

A can complete a work in 15 days

So, In 1-day, A can do =

$\frac{1}{15}$

th of work

B alone can do the work in 10 days

So, In 1-day, B can do =

$\frac{1}{10}$

th of work

But, it is given that B works only for 5 days and then leaves A alone

∴ Amount of work done by B in 5 days =

$\frac{5}{10} = \frac{1}{2}$

So, The remaining amount of work that A will do alone is = 1 – ½ = ½

Now,

If  

$\frac{1}{15}$

th of work is done by A in 1 day

Then, ½ of the work will be done by A in = 

$\frac{15}{2}$

= 7.5 days.

If B works at it for 5 days and leaves then A alone can finish the remaining work in 7.5 days.

 Then, ½ of the work will be done by A in = = 7.5 days.

$Answered by </p><p></p><p>PRKGoes$

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