Question

It takes 3/7 tonnes of sand to make a tonne of concrete. Harriet has 3 3/5tonnes of sand.

How much concrete, in tonnes, can she make?
Give your answer as a fraction in its simplest form.

Answer 1

Harriet can make 8 2/5 tonnes of concrete from 3 3/5 tonnes of sand, using the provided ratio of 3/7 tonnes of sand for each tonne of concrete.

Step-by-step explanation:

To calculate how much concrete Harriet can make from 3 3/5 tonnes of sand, we use the given ratio which is 3/7 tonnes of sand for each tonne of concrete. First, we convert Harriet's sand quantity to an improper fraction, which is 18/5 tonnes. Next, we set up a proportion to find out how many tonnes of concrete can be made.

We have 3/7 tonnes of sand = 1 tonne of concrete, so with 18/5 tonnes of sand we can calculate:

(3/7) tonnes of sand : 1 tonne of concrete = (18/5) tonnes of sand : x tonnes of concrete

Solving for x gives us:

x = (18/5) * (7/3) tonnes of concrete

x = (18*7)/(5*3) tonnes of concrete

x = (126/15) tonnes of concrete

x = 8 2/5 or 8.4 tonnes of concrete.

Harriet can make 8 2/5 tonnes of concrete from her sand.