Question

Write an equation and solve:

An iced cake costs 10p more than a plain cake. Sarah bought two of each cake. They cost £1 altogether. What is the cost of an iced cake?

Answer 1

55p

Explanation:

iced cake = 10p more than a plain cake

iced cake = 10p + plain cake

iced cake and a plain cake together = £1

iced cake + plain cake = £1

if iced cake = 10p + plain cake, we can plug this into our second formula to get

(10p + plain cake) + plain cake = £1

10p + 2 * plain cake = £1 = 100p

subtract 10p from both sides to isolate the variable and its coefficient

2 * plain cake = 90p

divide both sides by 2 to isolate the variable

plain cake = 45p

iced cake = 10p + plain cake = 55p