Let x be the number of CDs we buy and y the number of CDs we sell.
Each CD sell for $1.5, then the total of money we earn is $1.5y.
Each CD bought for $5, then the total money spent is $-5x
Add the above values like this:
1.5y-5x
We have $20, add them like this:
1.5y-5x+20
Since we want to have<span> at least $10 left when you leave the store, then
we deduce the equation:
</span>
Each CD sell for $1.5, then the total of money we earn is $1.5y.
Each CD bought for $5, then the total money spent is $-5x
Add the above values like this:
1.5y-5x
We have $20, add them like this:
1.5y-5x+20
Since we want to have<span> at least $10 left when you leave the store, then
we deduce the equation:
</span>