Answer:
16.2p (If lemonade is .75p, if not substitute in the equation below)
Explanation:
In 4 liters, there would be 3 liters of lemonade and 1 liter in juice.
I am assuming 75p is meant to be .75p
So 4 liters costs: (1 x 1.8) + (3 x .75) = 4.05
We need 16 so: 4.05 x 4 = 16.2