At a particular music store, cds are on sale at $11.00 for the first one purchased and $9.00 for each additional disc purchased. maria spends $65.00 on cds. how many cds has maria purchased? 6 7 8 9

Well first subtract the 11 from the first CD from the total of 65 so She spent $54 on the CD's that were $9.
Divide 54/9 to find out how much she spent per CD. You get a total of 6 CD's. Add on the 1 $11 one and you get a total of 7 CDs in total

-Calypso, 8th

So

we know she bought at least 1 so we minus the first 11
65-11=54
now, they are all 9 dollars
how many 9's in 54?
54/9=6

fisrt one=1
last ones are 6
6+1=7

7 cds purchased