A man can do a piece of work in 6 days, but with the help of his son, he can do it in 3 days. In what time can the son do it alone?	Pick one:
A) 5
B) 7
C) 6
D) 8
E) 9
Son's 1day's work = (1/3)-(1/6) = 1/6   The son alone can do the work in 6 days   Answer is 6
<result>C</result>
A man can do a piece of work in 6 days, but with the help of his son, he can do it in 3 days. In what time can the son do it alone?