Answer:
Dont know the answer but good luck
Step-by-step explanation:
I dont know if this helps but that what I came up with
0.6*3.98+1.8*2.49 =6.87 total cost
3
10:15=2:3
6:x=10:(15-10)=2:1
x=3
there are 64 ways to rearrange books on a shelf