Question 162761
Let x be the number of cds that cost $7.5 each.
Let y be the number of cds that cost $6.5 each.
The money spent on the $7.5 cds is 7.5x
The money spent on the $6.5 cds is 6.5y.
Now use the following relationships to set up a system of two equations:
(1) the total number of cds = 12
(2) the total money spent = 82

So 
x + y = 12    ..............(1)
7.5x + 6.5y = 82 ...........(2)

Solving  equation (1) for y, we have
y = 12 - x   ...............(3)
Substituting y = 12 - x into equation (2), we have
7.5x + 6.5(12 - x) = 82
Solving for x, we obtain:
7.5x + 78 - 6.5x = 82
x + 78 = 82
x = 4

Substituting x = 4 into equation (3) to find y, we get
y = 12 - x = 12 - 4 = 8

So Jerome bought 4 $7.5 cds, 8 $6.5 cds.