Answer:
£16.20
Explanation:
If F is litres of fruit juice, and L is litres of lemonade, then we can write a proportion:
F / L = 1 / 3
Cross multiply:
L = 3F
The total volume is 16 litres, so:
F + L = 16
Substitute and solve:
F + 3F = 16
4F = 16
F = 4
L = 12
There are 4 litres of fruit juice and 12 litres of lemonade.
The total cost is:
C = 1.80 F + 0.75 L
C = 1.80 (4) + 0.75 (12)
C = 16.2
The cost is £16.20.