A and B can finish a work in 10 days while B and C can do it in 18 days. A started the work, worked for 5 days, then B worked for 10 days and the remaining work was finished by C in 15 days. In how many days could C alone have finished the whole work ?
Choose one
A) 30 days
B) 15 days
C) 45 days
D) 24 days
E) None of these
Let C completes the work in x days.   Work done by (A + B) in 1 day = 1⁄10   Work done by (B + 45 days) in 1 day = 1⁄18   A’s 5 days’ work + B’s 10 days’ work + 45 days’s 15 days’work = 1   or (A + B)’s 5 days’ work + (B + 45 days)’s 5 days’ work + 45 days’s 10 days’ work = 1   or 5⁄10 + 5⁄18 + 10⁄x = 1 or x = 45 days   Answer 45 days
<result>C</result>
A and B can finish a work in 10 days while B and C can do it in 18 days. A started the work, worked for 5 days, then B worked for 10 days and the remaining work was finished by C in 15 days. In how many days could C alone have finished the whole work ?