streamline bicycles produce two kinds of bikes, mountain bikes and road bikes. It takes 4 hours to build a mountain bike and 3 hours to build a road bike. The company has 21 employees, each with a 40 hour work week. Due to demand, they must produce at least 250 total bikes each week. If they profit $75 on each mountain bike and $60 on each road bike, how many of each type should they produce in a week to maximize their profit?