A bicycle store costs $3500 per month to operate. The store pays an average of $65 per bike. The average selling price of each bicycle is $135. How many bicycles must the store sell each month to break even?
Let x be the number of bicycles the store sells each month
Total cost = Total revenue
Cost of operating the store + Cost of buying bicycles = Revenue from selling bicycles
$3500 + $65x = $135x
$135x - $65x = $3500
$70x = $3500
x = $<<50=50>>50
The store must sell 50 bicycles each month to break even. Answer: \boxed{50}.