Answer:
knife = £5.52
Step-by-step explanation:
The 2 equations are
k = 3s → (1)
9s + 12k = 82.8 → (2)
Substitute k = 3s into (2)
9s + 12(3s) = 82.8
9s + 36s = 82.8
45s = 82.8 ( divide both sides by 45 )
s = 1.84
Substitute s = 1.84 into (1)
k = 3 × 1.84 = 5.52
The cost of 1 knife is £5.52
