A company produces coffee makers. The labor cost of assembling one coffee maker during the regular business hours is $2.65. If the work is done in overtime, the labor cost is $3.75 per unit. The company must produce 660 coffee makers this week, and does not want to spend more than $1903 in labor costs. What is the smallest number of units that must be assembled during the regular hours?

520

Explanation:

Let's say the x = smallest number of units that must be assembled during the regular hours, and 660-x is the number of units that can be assembled in overtime. Then, the total cost should be smaller than or equal to cost1 * x + cost2*3.75

⇒ (x * 2.65) + ((660 - x) * 3.75) < = 1903

⇒ x * (2.65 - 3.75) + (660 * 3.75) < = 1903

⇒ 1.1 * x > = 2475 - 1903

⇒ 1.1 * x > = 572

⇒ x > = 520