Answer:
a) 18 rows of bricks are needed
b) 2.25 times b
0.375 times (b - 1)
46.875 inches
18 rows
Step-by-step explanation:
* Lets explain how to solve the problem
a)
- The height of each brick is the shortest edge
- The shortest age is 2 1/4 inch ⇒ (2.25 inches)
- If b is the number of the rows of bricks
∴ The height of the bricks = 2.35 × b
- The height of the mortar is 3/8 inches ⇒ (0.375 inch)
- All rows of bricks covered by mortar on top except the last row
- The height of mortar = 0.375 × (b - 1)
- The height of the wall is 1 1/8 (1.125) inches less than 4 feet
∵ 1 foot = 12 inches
∵ 4 feet = 12 × 4 = 48 inches
∴ The height of the wall = 48 - 1.125 = 46.875 inches
- The sum of the total height of bricks and the total height of mortar
is equal to the height of the wall
∴ 2.25 b + 0.375(b - 1) = 46.875
- By simplify it
∴ 2.25 b + 0.375 b - 0.375 = 46.875
∴ 2.625 b - 0.375 = 46.875
- Add 0.375 for both sides
∴ 2.625 b = 47.25
- Divide both sides by 2.625
∴ b = 18
∴ 18 rows of bricks are needed
b)
* Lets complete the missing
- The total height of the bricks in inches is equal to 2.25 times b
- The total height of the mortar is equal to 0.375 times (b - 1)
- Their sum is equal to the height of the wall or 46.875 inches
- If I write this as an equation and solve for b, then the result is
18 rows of bricks
