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Question

Block Wall
A wall is to be constructed with concrete blocks.

Dimensions of wall- 20' X 16' X 8'

Dimensions of blocks- 8" X 8" X 16"

Calculate number of blocks needed.

Notes: Blocks are actually 3/8" smaller for allowance of mortar.  Dimensions are finish dimensions.

I have attached an illustration.

Thanks.

Change inches to feet.
8"×8"×16" = (2/3)'×(2/3)'×(4/3)'

Each course of bricks has:
two full rows (blue) that terminate at the outside of the structure
two inside rows (red) that terminate at a brick.

Each course is 2/3 ft high.
8 ft × 1 course/(2/3 ft) = 12 courses
The structure has 12 courses of bricks.

Consider course 1. The full rows are 20 feet long.
20 ft × 1 brick/(4/3 ft) = 15 bricks
Each full row contains 15 bricks

The inside rows are (16 - 2(2/3)) =  44/3 feet long.
44/3 ft × 1 brick/(4/3 ft) = 11 bricks
Each inside row contains 11 bricks

Each odd-numbered course contains 2×15 + 2×11 = 52 bricks.

Similarly, an even-numbered course has 12 bricks in each full row and 14 bricks in each inside row, for a total of 52 bricks.

Since each course contains 52 bricks. the structure uses a total of 12×52 = 624 bricks.

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