Answer:
Henry is 5kg short of cement.
Explanation:
4:3:1
Cement : Sand : Gravel
We can also write the ratio as:
4 x Gravel : 3 x Gravel : 1 x Gravel
Therfore a logical "x" would be the amount of gravel.
If we substitute gravel with x and put it in an equation we get:
4x+3x+x=120
8x=120
x=120/8
x=15
This way we can check if each value is correct.
x = Weight of Gravel = 15kg Correct
3x = Weight of Sand = 45kg Correct
4x = Weight of cement = 60kg WRONG!
The actually weight of cement is 55kg.
Therefore Cement is 5kg short.