John can do a piece of work in 30 days while michael can do it in 40 days. In how many days will they finish it together?  Choose the correct option.
A) 17 1/7 days	B) 27 1/7 days	C) 23 2/7 days	D) 16 4/11 days	E) 17 5/11 days
Explanation:   1/30 + 1/40 = 7/120   120/7 = 17 1/7 days   17 1/7 daysnswer: 17 1/7 days
<result>A</result>
John can do a piece of work in 30 days while michael can do it in 40 days. In how many days will they finish it together?