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Dimensions = 5 ft x 7 ft
Brick = 4 in x 12 in
1.- Convert ft to in
1 ft -------------------- 12 in
5 ft ------------------- x
x = (5 x 12) / 1
x = 60 in
1 ft -------------------- 12 in
7 ft -------------------- x
x = (7 x 12) / 1
x = 84 in
2.- Calculate the area of the wall
Area = 60 x 84
= 5040 in^2
3.- Calculate the area of a brick
Area = 4 x 12 = 48 in^2
4.- Divide the area of the wall by the area of the brick
Number of bricks = 5040 / 48
= 105
There will be 105 brick on the wall.