Given:
Let x be the number of the cards and y be the number of the package.
Given that the number of cards is at least 4 more than twice the number of packages.
[tex]x=2y+4[/tex]Given that mailing costs no more than $500 and the cost of mailing a card is $3 and for a package, the cost is $7.
[tex]3x+7y=500[/tex]Substitute x=2y+4 in this equation, we get
[tex]3(2y+4)+7y=500[/tex][tex]6y+8+7y=500[/tex][tex]13y=500-8[/tex][tex]y=\frac{492}{13}[/tex][tex]y=37.8[/tex]Let y=37 and substitute in x=2y+4, we get
[tex]x=2\times37+4[/tex][tex]x=78[/tex]Hence the number of cards = 78 and the number of packages =37.
The total cost for this is $493 not more than $500.
