Answer :
Answer:
Bob the builder need 180 kg sand.
Step-by-step 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.
[tex]x+3x+4x=480[/tex]
[tex]8x=480[/tex]
Divide both sides by 8.
[tex]x=60[/tex]
The amount of sand is 3x, so
[tex]3\times 60=180[/tex]
Therefore bob the builder need 180 kg sand.
