Question

10 cakes cost £3.50. how much do 3 cakes cost?

Answer 1

Solving: Rule of three (directly proportional)
10 cakes → £3.50
3 cakes → y

$\frac{10}{3} = \frac{3.50}{y}$
Product of extremes equals product of means:
$10*y = 3.50*3$
$10y = 10.5$
$y = \frac{10.5}{10}$
$y = 1.05$

Therefore:
3 cakes cost £1.05

Answer 2

So u need to use 3.50/10*3

0.35*3=1.05