Question

If 3 men or 6 boys can do a piece of work in 10 days, working 7 hours a day; how many days will it take to compete a piece of work twice as large with 6 men and 2 boys working together for 8 hours a day ?

Answer 1

Total Amount of work completed

Taking man-day-hour we get

9*10*7=630 man-day-hour

Now twice the job as given in question

So 630*2=1260 man-day-hour

Now take day as X

So 1260=8*8X

X=1260/64=>19.68 so 20 days

Time taken to complete job 20 days