18 men can do a work in n days. If 15 men started the work and after 10 days, (n – 5) more men joined the work and the remaining work was completed in 7 days, then find the value of n?
A. 10
B. 35
C. 15
D. 20
E. None of these
Sol:
18 * n = 15 * 10 + (15 + n – 5) * 7
18n = 150 + 10 * 7 + 7n
11n = 220
n = 20
