Question

A knife is three times the cost of a spoon.

9 spoons and 12 knives cost £82.80.
Work out the cost of 1 knife

Answer 1

Answer: £5.52

Step-by-step explanation: I done this same question as you

Answer 2

cost of knife = £5.52

Explanation:

Assume:

Cost of Knife = a

Cost of Spoon = b

a = 3b ----------------------(1)

12a + 9b = £82.80 -------(2)

Substitute equation (1) in equation (2)

12 * (3b) + 9b = £82.80

36b + 9b = £82.80

45b = £82.80

b = £1.84

Therefore, cost of knife = a = 3 * £1.84 = £5.52