A. 7
B. 8
C. 9
D. 10
P and Q need 8 days to complete a work. Q and R need 12 days to complete the same work. But P, Q and R together can finish it in 6 days. How many days will be needed if P and R together do it?
A. 7
B. 8
C. 9
D. 10
A. 7
B. 8
C. 9
D. 10