Q. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. The number of days taken in completing the wotk were ?

1. 14(2/3)kmph
2. 15(2/3)kmph
3. 16(2/3)kmph
4. 17(2/3)kmph