15 men can complete work in 210 days. They started work but at end of 10 days, 15 additional men, with double efficiency, were inducted. How many days in all, did they all take to finish the work?
A. 220/3 days
B. 151/2 days
C. 251/4 days
D. 70 days
E. None of these
Answer: Option E
Solution (By Examveda Team)
Initial Men = 15.These 15 men can finish the work in 210 days.
Total Work = 15 * 210 men-days
They work for 10 days.
Now, 15 men with double efficiency are added.
So, total men = 15 + 2* 15 = 45 men as initial efficiency.
Now, Rest Work will finish in,
=[ 15 * (210 - 10) ]/45
= 200/3 days.
Thus, total time taken to finish the work,
= 10 + 200/3 = 230/3
= 76.66 days.
Total time taken to finish the work,
= 10 + {15 * (210 - 10)}/ (15 + 2*15)
= 230/3 days.