## Algebra 1

$100$ cards
Let number of cards be x. The cost for pristine printing cards would be $15 + 0.1 x$ The cost for printing place cards is $10 + 0.15 x$ Set these two equations equal: $15 + 0.1x = 10 + 0.15x$ Multiply each side by $100.$ $1500 + 10x = 1000 + 15x$ Subtract $10x$ from each side $1500 = 1000 + 15x-10x$ $1500 = 1000 + 5x$ Subtract $1000$ from each side to isolate $5x.$ $500 = 5x$ Divide both sides by $5$ to isolate $x.$ $x = 100$