Ravi can do a piece of work in 15 days while Prakash can do it in 30 days. In how many days will they finish it together?  Choose the correct choice.
A) 11 days  B) 9 days  C) 8 days  D) 12 days  E) 10 days
1/15 + 1/30 = 3/30   10/1= 
<gadget id="calculator">10/1</gadget>
<output>10</output>
10 days   ANSW10 daysR:10 days
<result>E</result>
Ravi can do a piece of work in 15 days while Prakash can do it in 30 days. In how many days will they finish it together?