Bricks have a mass of 1.75kg each.How many bricks are there in 21/4tonnes?

Answer 1

First, we need to convert 21/4 tonnes to kilograms by multiplying by 1000:
21/4 * 1000 = 5250 kg

Next, we divide the total mass of bricks by the mass of one brick to find the number of bricks:
5250 kg / 1.75 kg/brick = 3000 bricks. Answer: \boxed{3000}.