Question

A contractor employed 200 workers. They finished 5/6 of the work in 10 days. Due to rain, the work stopped and also destroyed 2/5 of the work. After the rain 150 workers came to work. In how many days will the remaining work be completed?
1)10 day 2)16 day 3) 9 day 4) 8 day​

Answer 1

Answer:

Step-by-step explanation:

Given 5/6 work is completed by 200 workers in 10 weeks

Therefore in 1 week they will be able to complete 5/60 = 1/12 of work.

So 1 man will be able to complete 1/2400 work in 1 week.

Now because of rain half of completed work is washed away.

Therefore completed work will be 5/6 x 1/2 = 5/12

Let the remaining work be p

Therefore p + 5/12 = 1

Or p = 1 – 5/12

Or p = 7/12

According to the question 140 men are available to complete the remaining work.

So work completed in 1 7/120 q = p

will be 1/2400 x 140 = 7/120

Now let q weeks are required to finish the work.

Then 7/120 q = p

       7/120 q = 7/12

        Or q = 120 / 12

       Or q = 10 weeks.

Therefore total time required to complete the work in 10 week will be

    10 + 4 + 10 = 24 weeks              

Answer 2

Answer:

Total work = 200 men* 100 days * 6/5 = 24,000 man days

Work finished in 100 days by 200 workers = 24,000*5/6 = 20,000

Work destroyed by rain = 20,000 * 2 /5 = 8,000

Work left = 24,000 - 20,000 + 8,000 = 12,000

150 workers can complete this in 12,000/150 = 80 days