JAMB - Mathematics (2002 - No. 14)
The time taken to do a piece of work is inversely proportional to the number of men employed. if it takes 45 men to do a piece of work in 5 days, how long will it take 25 men?
15 days
12 days
5 days
9 days
Explanation
The time (t) to do the work is inversely proportional to the number of workers (n).
\(\implies t \propto \frac{1}{n}\)
\(t = \frac{k}{n}\)
\(5 = \frac{k}{45} \implies k = 45 \times 5 = 225\)
\(\therefore t = \frac{225}{n}\)
For 25 men, \(t = \frac{225}{25} = 9\)
\(\therefore\) 25 men will do the work in 9 days.
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