Minimum number of 50 kg cement bags per cubic metre of concrete for a mix corresponding to crushing strength 280 kg/cm² at 28 days, are

Minimum number of 50 kg cement bags per cubic metre of concrete for a

1.	Minimum number of 50 kg cement bags per cubic metre of concrete for a mix corresponding to crushing strength 280 kg/cm² at 28 days, are
A.	5.0
B.	6.5
C.	7.0
D.	7.5
Answer» C. 7.0