A,B,C together can do a work in 8 days. A alone can do the work in 30 days and B alone can do the same work in 20 days. Find in what time C alone can do that work?  Choose the correct choice:
A) 16days  B) 20.8days  C) 24days  D) 28.5days  E) 32.4days
The required answer is = 8*30*20 / 30*20-8(30+20)   = 4800/200= 
<gadget id="calculator">4800/200</gadget>
<output>24</output>
24days   Answer is 24days
<result>C</result>
A,B,C together can do a work in 8 days. A alone can do the work in 30 days and B alone can do the same work in 20 days. Find in what time C alone can do that work?