A can do a piece of work in 15 days and B can do it in 15 days and C can do it 20 days. They started the work together and A leaves after 2 days and B leaves after 4 days from the beginning. How long will work lost?
Answers:
A) 15
B) 10
C) 12
D) 11
E) 13
2/15 + 4/15 + x/20 = 1   x = 12 Answer: 12
<result>C</result>
A can do a piece of work in 15 days and B can do it in 15 days and C can do it 20 days. They started the work together and A leaves after 2 days and B leaves after 4 days from the beginning. How long will work lost?