Question

You are planning for a breakfast party and need enough milk for 20 people. Each person will drink about 200mL of milk. Which us the bat estimate of the amount of the milk you should prepare: 400mL or 4L?Explain.

Answer 1

1 liter = 1000 ml 
 so  4L is the amount of the milk you should prepare

Answer 2

You won't get 400mL because you are giving it to 20 people, and 400 mL would only give enough for 2 people. So 4L.