gmatbusters wrote:
Contractor X employs 200 men to build a dam. They finish 5/6 of the work in 10 months. Then rain sets in and not only does the work remain suspended for 4 months but also half of the work already done is washed away. After the rain, when the work is resumed, only 140 men turn up. The total time in which the contractor is able to complete the work assuming that there are no further disruptions in the schedule is
(a) 25 months
(b) 26 months
(c) 24 months
(d) 20 months
(e) None of these
GMATbuster's Collection
• 200 men can complete \(\frac{5}{6}^{th}\) work in 10 months
• 200 men can complete 1 work in \(\frac{10}{(5/6)}\) months = \(6*\frac{10}{5} = 12\) months
o Ideally only 12 – 10 = 2 months of work should have been left.
However, half of the work done by them so far got wasted. They worked for 10 months and if half of it is wasted then that means 5 months of work is wasted.
• So, now the 200 men need to complete = 5 month of rework + 2 months of work left = 7 months of work.
However, we have only 140 men, so we’ll need to more time.
• 200 men complete the work in 7 months
• 1 man can complete it in 7*200 months
• 140 men can complete the work in \((7*\frac{200}{140}) = 10\) months.
Thus, total time taken to complete the project = 10 months + 4 months of delay + 10 months = 24 months.
Correct Answer:
Option C