If eight men can dig a hole in 4 hours, how long will take the five men to dig the same hole?

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If eight men can dig a hole in 4 hours, how long will take the five men to dig the same hole?

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Answer 1 · 2015-03-30T13:08:43

6.4 hours;
You use the proportion (inversely proportionality)
if n° of men decreases $8 \to 5$ $8->5$
Time must increase $4 \to x$ $4->x$ so inverting:
$\frac{8}{5} = \frac{x}{4}$ $8/5=x/4$
$x = \frac{32}{5} = 6.4$ $x=32/5=6.4$

Answer 2 · 2015-03-30T13:09:10

(Assuming the men don't get in each others' way)

if 8 men can dig a hole in 4 hours
the hole represents $8 \times 4 = 32$ $8xx4 = 32$ man-hours of work.

5 men can complete 32 man-hours of work in
$(32 cancel(man) hours)/(5 cancel(men)) = 6.4 hours$

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If eight men can dig a hole in 4 hours, how long will take the five men to dig the same hole?

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