A,B,C can complete a piece of work in 21,6,12 days. Working together, they complete the same work in how many days?
Choose the correct choice from the following: A) 2 B) 4/5 C) 7/9 D) 10 E) 84/25
A+B+C 1day work = 1/21 + 1/6 + 1/12 + +  1= 
<gadget id="calculator">+ +  1</gadget>
<output>1</output>
1/21 + 1/6 + 1/12= 25/84   A,B,C together will complete the job in 84/25 days   Answer is 84/25
<result>E</result>
A,B,C can complete a piece of work in 21,6,12 days. Working together, they complete the same work in how many days?