A contract is to be completed in 52 days and 125 identical robots were employed, each operational for 7 hours a day

Q. A contract is to be completed in 52 days and 125 identical robots were employed, each operational for 7 hours a day. After 39 days, five-seventh of the work was completed. How many additional robots would be required to complete the work on time, if each robot is now operational for 8 hours a day?

            (A) 50               (B) 89                         (C) 146                        (D) 7

Ans: 7

Sol:

W=47775 Robot hrs.

Left work
=47775−125×7×39
=13650 Robot hrs.

13×x×8=13650
x=131.25

Addition robot required
=131.25−125
=6.25=7