A grocer wanted to mix 19 liters milk of $2.2 with 1 kg cacao to make a mixture of hot chocolate. What should be the cost of milk, if the total mixture costed 3 dollars?

for this, I'm going to assume that the cacao powder costed $2.2. If the cacao costs $2.2 then the milk will cost $0.8.

Step-by-step explanation:

If you subtract 2.2 from 3 then you get 0.8. Also if you add 2.2 with 0.8 then you get 3. another way to simplify it is to add one zero on the end, like this 22+8=30.