1. 

A and B together can complete a task in 7 days. B alone can do it in 20 days. What part of the work was carried out by A?

I. 

A completed the job alone after A and B worked together for 5 days.

 II. 

Part of the work done by A could have been done by B and C together in 6 days.

A. I alone sufficient while II alone not sufficient to answer
B. II alone sufficient while I alone not sufficient to answer
C. Either I or II alone sufficient to answer
D. Both I and II are not sufficient to answer
E. Both I and II are necessary to answer

Answer: Option A

Explanation:

B's 1 day's work = 1
20

(A+ B)'s 1 day's work = 1
7

 I. (A + B)'s 5 day's work = 5
7

Remaining work = 1 - 5 = 2 .
7 7

2 work was carried by A.
7

II. is irrelevant.

Correct answer is (A).