If 15 persons can do a job in 30 clays, then 30 persons with twice the efficiency can do the same job in how many days?
A. 7
B. 3.5
C. 5
D. 7.5
Answer:D
If 15 persons can do a job in 30 clays, then 30 persons with twice the efficiency can do the same job in how many days?
A. 7 B. 3.5 C. 5 D. 7.5