1/30 + 1/40 = 7/120
120/7 = 17 1/7 days
Ravi can do a piece of work in 30 days while Prakash can do it in 40 days. In how many days will they finish it together?
Options:
1. 17 1/7 days
2. 17 1/8 days
3. 17 5/7 days
4. 17 3/7 days
5. 13 1/7 days