1. ## making concrete

hi
I have to make a concrete base which is 1.68 metres cubed.
How do i work how much cement, sand and gravel to use in metric system?
so 1 part cement to 2 parts sand and 3 parts gravel.

2. Originally Posted by mat
hi
I have to make a concrete base which is 1.68 metres cubed.
How do i work how much cement, sand and gravel to use in metric system?
so 1 part cement to 2 parts sand and 3 parts gravel.
All together there are 6 parts. That means the complete mixture contains:

$\underbrace{\dfrac16 \cdot 1.68\ m^3}_{cement} + \underbrace{\dfrac26 \cdot 1.68\ m^3}_{sand} + \underbrace{\dfrac36 \cdot 1.68\ m^3}_{gravel}$