A man can do a piece of work in 15 days, but with the help of his son, he can do it in 6 days. In what time can the son do it alone?
Options.
A) 13  B) 9  C) 15  D) 8  E) 10
Son's 1day's work = (1/6)-(1/15) = 3/30= 1/10   The son alone can do the work in 10 days   Answer is 10
<result>E</result>
A man can do a piece of work in 15 days, but with the help of his son, he can do it in 6 days. In what time can the son do it alone?