Renu can do a piece of work in 6 days, but with the help of her friend Suma , she can do it in 5 days. In what time Suma can do it alone? Select the correct option.
A) 10
B) 12
C) 14
D) 15
E) 30

Rationale: renu â € ™ s one day â € ™ s work = 1 / 6 suma â € ™ s one day â € ™ s work = 1 / 5 - 1 / 6 = 1 / 30 suma can do it alone in 30 days . answer : e
Answer: E