Combine 250 mL, 500 mL, 750 mL and 3 L. How many liters is this

4.5

Step-by-step explanation:

250 mL= 0.25 L  500 mL= 0.5 L  750mL= 0.75 L+3L

Because you have more friends than oranges, you can assume that each person will only get part (or a fraction of) an orange. 
If you divide 5 oranges for 6 people, your equation looks like 5 / 6, so each person gets 5/6th of an orange, or about 0.833 oranges per person.

Hope this helps :)