Question

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

Answer 1

Answer:

see the explanation

Step-by-step explanation:

Let

x ---> kilograms of cement needed

y ----> kilograms of sand needed

z ----> kilograms of gravel needed

we know that

$x:y:z=1:3:4$ ----> $x+y+z=1+3+4=8$

$x+y+z=480\ kg$

Divide 480 by 8

$480/8=60$ ----> scale factor

Multiply the scale factor by the ratio $1:3:4$

Find out the kilograms of cement needed

$60(1)=60\ kg$

Find out the kilograms of sand needed

$60(3)=180\ kg$

Find out the kilograms of gravel needed

$60(4)=240\ kg$