129
This cannot be answered without knowing the width and depth.
A typical 80-pound bag of concrete mix yields about 0.6 cubic feet of concrete. A 3-yard mixer has a capacity of 81 cubic feet (3 cubic yards). To fill the mixer, you would need approximately 135 bags of 80-pound concrete mix, since 81 cubic feet divided by 0.6 cubic feet per bag equals about 135 bags.
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.
4.4 bags
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.
Typically, one 50-pound bag of concrete is needed per fence post.
Forty five 80 pound bags of cement are needed to make one cubic yard of concrete.
Depending on the use of the concrete, between 5-6 bags.
20
The number of bags of concrete needed for setting fence posts depends on the size and number of posts. Typically, one 50-pound bag of concrete is enough for one 4x4 fence post. So, if you have 10 fence posts, you would need 10 bags of concrete.
Typically, one bag of concrete is needed per post.
To determine how many 80-pound bags of concrete are needed to fill a 55-gallon drum, first calculate the volume of the drum. A 55-gallon drum holds about 7.4 cubic feet (since 1 gallon is approximately 0.133 cubic feet). An 80-pound bag of concrete typically yields about 0.6 cubic feet. Therefore, you would need approximately 12 to 13 bags of concrete to fill the drum.
10 bags will give you 6'2/3", seven bags will give you 11 bags will give you 7'1/3". Each bag is 2/3 cu feet.
This cannot be answered without knowing the width and depth.
Typically, one bag of concrete is needed per fence post.
25
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.