A brick walkway measuring 3m by 5m is to be built. Each brick measures 20cm x 10cm. How many bricks will it take to build the walkway?

Both 3 m (300 cm) and 5 m (500 cm) are divisible by both 20 cm and 10 cm.

Area of the walkway = 300 × 500 cm²
Area of each brick = 20 × 10 cm²

Number of bricks to build the walkway
= (300 × 500) ÷ (20 × 10)
= 750

15/0.02 = 750 bricks

1 m = 100 cm
3 m by 5 m = 300 cm by 500 cm = (300)(500) = 150000 cm^2
20 cm by 10 cm = 200 cm^2
150000 / 200 = 750 bricks

first option: convert 3m and 5m to cm, find the are of the walkway in cm squared, find the area of one brick, divide the area of the walkway by the area of one brick
5m = 500 cm
3m = 300 cm
Area of walkway = 500cm * 300cm = 150000 square cm
Area of brick = 20cm * 10cm = 200 square cm
No. of Bricks = 1500 / 200 = 750 bricks

second option. convert the 20cm and 10 cm to m
20cm = 0.2 m
10cm = 0.1 m

Area of walkway = 3m * 5m = 15 square meters
Area of Brick = 0.2m * 0.1m = 0.02m square meter
No. of bricks = 15 / 0.02 = 750 bricks