Answer:
Step-by-step explanation:
<u>Given</u>
<u>Solution</u>
there will be 8 boxes filled and 7 extras books
11
5x+15+20=90
5x+35=90
-35 from both sides
5x=55
divide both sides by 5
x=11
16 +6=22 9 +x = 22
x=22-9
x= 13