Question

I used 8 bags of sand for 12m squared how much will I need for 15 m squared

Answer 1

every 12m, your need to use 8 bags.Therefore you need to use 0.66666667 every 1m(8/12 = 0.66666667). 0.66666667 x 15 = 10
You need 10 bags of sand for a 15m squared