A company manufactures both mountain bikes and trail bikes. The cost of materials for a mountain bike is $60, and the cost of materials for a trail bike is $40. The cost of labor to manufacture a mountain bike is $90, and the cost of labor to manufacture a trail bike is $50. During a week in which the company has budgeted $1,500 for materials and $2,100 for labor, how many mountain bikes does the company plan to manufacture?