How many liters are in 21 cups? if 1L=4.2cups
i don't understand how to do it

5 L

Step-by-step explanation:

As given in question,

1 L can fill 4.2 cups.

So, 1 cup can hold L of fluid.

Therefore,

21 cups can hold = × 21

                            = 5 L

So, there is 5 L of fluid in 21 cups.