The efficiencies of A, B, and C are in the ratio 2 ∶ 5 ∶ 3. Working together, they can complete a task in 12 days. In how many days can A alone complete 30% of that task?

The efficiencies of A, B, and C are in the ratio 2 ∶ 5 ∶ 3. Workin

1.	The efficiencies of A, B, and C are in the ratio 2 ∶ 5 ∶ 3. Working together, they can complete a task in 12 days. In how many days can A alone complete 30% of that task?
A.	20
B.	18
C.	15
D.	16
Answer» C. 15