10
This cannot be answered without knowing the width and depth.
Each 60 pounds bag of ready mix concrete will make .45 cubic foot of concrete. There are 27 cubic feet in a cubic yard. You will need 60 bags of 60 pound premixed concrete to make 1 cubic yard.
According to the related link below; the required amount to cover 1 square yard with 4 inches of concrete is 6.6 60 pounds bags.
The answer is, remarkably, 6. Answer: "6 sack" or "6 bag mix" has six bags of cement per cubic yard of concrete mix. Since each sack/bag contains 94 lbs of dry cement, this equals 564 lbs of cement per cubic yard of concrete.
20
about 60 60lb bags
27 bags of 30kg bags of concrete bargs
about 60 60lb bags
Forty five 80 pound bags of cement are needed to make one cubic yard of concrete.
40 bags of 90 will give you 1 yard
41 bags. Actual 40.5
According to the FAQ on the Sakrete web site, Sixty of their sixty pound bags of High Strength concrete mix will be required to make a cubic yard of concrete.
According to the related link below; the required amount to cover 1 square yard with 4 inches of concrete is 6.6 60 pounds bags.
Here's a link to a great concrete calculator that will compute that for you!
10
This cannot be answered without knowing the width and depth.