Question

Bob the builder is making 480 kg concrete mix. Concrete is made by mixing cement, sand and gravel in the ratio 1:3:4 how much sand does he need

Answer 1

Bob the builder need 180 kg sand.

Explanation:

The amount of concrete mixture is 480 kg. It is given that concrete is made by mixing cement, sand and gravel in the ratio 1:3:4.

Let the amount of cement, sand and gravel in concrete mixture be x, 3x, 4x respectively.

`x+3x+4x=480`

`8x=480`

Divide both sides by 8.

`x=60`

The amount of sand is 3x, so

`3* 60=180`

Therefore bob the builder need 180 kg sand.

Answer 2

1x+3x+4x = 480

8x = 480

xdivide by 8

x=60

cement: 1x = 60kg

sand : 3x = 3*60 = 180kg

gravel : 4x = 4*60 = 240kg