X is able to do a piece of work in 14 days and Y can do the same work in 20 days. If they can work together for 5 days, what is the fraction of work completed? Choose the correct choice from the following answers.
A) 15/28 B) 17/28 C) 13/28 D) 19/28 E) 11/28
Explanation :   Amount of work X can do in 1 day = 1/14   Amount of work Y can do in 1 day = 1/20   Amount of work X and Y can do in 1 day = 1/14+ 1/20= 17/140   Amount of work X and Y can together do in 5 days = 5 × (17/140) = 17/28   Answer : Option 17/28
<result>B</result>
X is able to do a piece of work in 14 days and Y can do the same work in 20 days. If they can work together for 5 days, what is the fraction of work completed?