FOIL method
First:
u squared times u squared equals to u to the fourth.
Outer and Inner:
8u squared + u squared equal 9u squared. Remember, the exponents don't change when adding!
Last:
8 times 1 equals 8
There is : 3 pencils
4 Bubble gums
2 sports cards
In each favor bag
50 + 20h = 100 + 10h
20h - 10h = 100 - 50
10h = 50
h = 50/10
h = 5 <== they will charge the same at 5 hrs
Percent of decrease :
Original - New / Original
so...
80 - 52 / 80 ---->
28/80
.35 multiply by 100 to get percent
35% increase Hope I helped if you have any questions let me know! :)