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
