Question

It takes one examiner 15 hours to mark 80 exam papers how long should it take five examiners to mark 80 exams papers

Answer 1

Answer: 3 hours

Step-by-step explanation:

Time taken by 1 examiner to mark 80 exam papers = 15 hours

∴ Time taken by 5 examiners to mark 80 exam papers = 15 ÷ 5 hours

                                                                                               = 3 hours

Answer 2

$\huge \bold{ \red{ \underline{{Solution }}}}$

Applying unitary method

One examiner take 15 hour to marks 80 exam paper.

So, in one hour he can mark = $\sf{ \frac{80}{15} \: paper}$

In 5 hour examiners can mark = $\sf \: 5 \times \frac{80}{15} = \frac{80}{3} papers$

So, we know 5 examiner can mark $\sf \: \frac{80}{3} paper \:in \: 1 \: hour$

So, to mark 1 paper the will take = $\sf \: 1 \div \frac{80}{3} = \frac{3}{80} \: of \: a \: paper.$

Thus, to mark 80 paper they will take = $\sf \frac{3}{80} \times 80 = 3 \: hour$

$\bf{ \color{blue}{Thus, \: it \: will \: take \: 3 \: hour \: for \: 5 \: examiner }} \\ { \bf{ \color{blue}\: to \: mark \: 80 \: papers.}}$