Question

150 workers were engaged to finish a piece of work in a certain number of days. Four workers dropped the second day, four more workers dropped the third day and so on. It takes 8 more days to finish the work now. Find the number of days in which the work was completed.

Answer 1

Correct Answer - 25 hours
Suppose that the work completed in n days
Total number of workers engaged for 1 day each
= 150 +146 +142 +…… to n terms
` n/2 xx[2xx 150 + (n-1) xx (-4)] =n = n (152 -2n)`
If 150 workers are engaged each day, time take= (n-8) days.
Number of workers engaged of 1 day = 150 (n-8)
n(152 - 2n) = 150 ( n-8) ` Rightarrow n^(2) -n-600 =0`
` Rightarrow (n-25) (n+24) =0`
` Rightarrow n=25 " " [ therefore, n ne -24]`