Question

Olive oil costs £3.50 for 1 litrehow much 200 ml of olive oil cost

Answer 1

3.50/5=£0.7

We divided by 5 because there is 1000 ml in 1 litre and we have to find out how much is in 200 ml.

The final answer is £0.7 for 200 ml

Answer 2

Data:
1 litre = 1000 mL

If:

1000 mL → £3.50
200 mL → y

Solving: Rule of three (directly proportional)

$\frac{1000}{200} = \frac{3.50}{y}$

Product of extremes equals product of means:

$1000*y = 3.50*200$
$1000y = 700$
$y = \frac{700}{1000}$
$y = 0.7\to \boxed{\boxed{y = \£0.70}}\end{array}}\qquad\quad\checkmark$