ratio and proportion algebra word problem

Question

In making a certain type of concrete, the ratio of cement to sand is 1:4. In making x barrels of this concrete, the number of barrels of cement used is

(1) x/5 (4) 4x

(2) x/4 (5) 1/5x

(3) x

Answer 1

For each barrel of concrete, 1/5 is cement and 4/5 is sand.

So, for x barrels of concrete, x/5 is cement and (4/5)x is sand.