Question

6. At a construction site, cement, sand, and gravel are used to make concrete. The ratio of cement to sand to gravel is 1 to 2.4 to 3.6. If a 150-lb bag of sand is used, how much cement and gravel must be used?

Answer 1

Mass of cement used is 62.5 lb

Mass of gravel used is 225 lb

Step-by-step explanation:

The ratio given here is cement to sand to gravel = 1 : 2.4 : 3.6

So, for 150 lb of sand

C : S : G = 1 : 2.4 : 3.6

`(C)/(S)=(1)/(2.4)\\\Rightarrow C=S(1)/(2.4)\\\Rightarrow C=150(1)/(2.4)\\\Rightarrow C=62.5\ lb`

Mass of cement used is 62.5 lb

`(S)/(G)=(2.4)/(3.6)\\\Rightarrow G=S(3.6)/(2.4)\\\Rightarrow C=150(3.6)/(2.4)\\\Rightarrow C=225\ lb`

Mass of gravel used is 225 lb