Ravi can do a piece of work in 20 days while Prakash can do it in 40 days. In how many days will they finish it together?
Pick one:
A) 13 1/3 days B) 15 1/3 days C) 17 1/3 days D) 17 7/3 days E) 18 1/3 days
1/20 + 1/40 =3/40   40/3   = 13 1/13 days   13 1/3 daysnswer: 13 1/3 days
<result>A</result>
Ravi can do a piece of work in 20 days while Prakash can do it in 40 days. In how many days will they finish it together?