Amanda owns a clothing store that sells graphic t-shirts. n is the number of shirts she sells each month. the revenue function of her store is r = 25n. the cost function of her store is c = 10n + 900. using your calculator, what is the break-even point of amanda's store?

The break-even point will be attained when the revenue is equal to the cost. That is 
     [tex]25n=10n+900[/tex]
     [tex]25n-10n=900[/tex]
     [tex]15n=900[/tex]
     [tex]n=60[/tex]

The break-even point is attained when n equals 60.