Answer:
Jessie needs 15/24 more gallons of paint.
Words such as more than us know that this problem is subtraction, info from this problem also lets us know that we need to subtract 15/8 - 5/6
To intrept this expression:
15/8 - 5/6
45/24 - 20/24
15/24
You make the fractions, with like denominators, then subtract only the numerators.
Hope this helps!