A can do a piece of work in 10 days; B can do the same in 20 days. How many days will it take the work to get finished if A and B work together?	Pick one:
A) 4.21
B) 5.32
C) 6.66
D) 7.52
E) 8.02
A completes 1/10th of the work in one day and B completes 1/20th.   (1/10)+(1/20)=(1/x)   3/20=1/x =&gt; x=20/3=6.66 days   Answer: 6.66
<result>C</result>
A can do a piece of work in 10 days; B can do the same in 20 days. How many days will it take the work to get finished if A and B work together?