Final answer:
Maria used 160ml of cream.
Step-by-step explanation:
To find how much cream Maria used, we need to set up a ratio between the milk and the cream. The ratio of milk to cream is 3:2. This means that for every 3 parts of milk, there are 2 parts of cream. Maria used 240ml of milk, so we can set up the equation 3/2 = 240/x, where x represents the amount of cream she used. To solve for x, we cross multiply and get 3x = 480. Dividing both sides by 3, we find that Maria used 160ml of cream.