Question

A science teacher has 0.4 liter of seawater. She gives each of her 22 students a container and a 5-milliliter spoon. She then asks her students to put two spoonfuls of seawater into their containers. How many milliliters of seawater will be left after all 22 students have filled their containers?

Answer 1

0.4 liter means 400 ml (milliliter).

We know that 1 spoon is 5 ml. Thus, if each student takes out 2 spoons, then each student will take out 10 ml of water.

There are 22 students, so each student will take out 220 ml.

Thus, the milliliters of seawater that will be left after all 22 students have filled their containers is:

$400-220=180$ ml

Answer 2

$400ml \div 10ml = 40ml \\ 40ml - 22ml = 18ml$
so the answer is 18milliliters