This is confusing! Help me show my work and explain:( Its only for number 15

Step-by-step explanation:
I'm not really sure if this is the correct answer but I tried
Answer: Jan had 2 more gallons of orange juice than matt
Explanation: each are making 10 gallons
so add 8 and 2 on jans chart since we get 10 gall total
and for Matt's chart we are doing the same thing add 6 and 4
but since we are only calculating how much more oj they had we basically subtract 8 with 6
and there you go!
srry if i explained it wrong