Coverage of pre mix concrete Drainage pipes, concrete, footings and foundations. Post your questions and find answers here

[tonypagett]

I need to work out how much pre mix concrete I need for a small project but am confused by the fact that [b]25Kg of general purpose pre mix[/b] concrete is said to cover 1687cubic cm but [b]25Kg of path mix[/b] will cover 3125cubic cm. Almost twice as much.

Any ideas please?