The cost, in dollars, of shipping x computers to California for sale is 3000 + 100x. The amount received when selling these computers is 400x dollars. What is the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost?
Setting the cost of shipping equal to the amount received gives us the equation 3000+100x = 400x. Subtract 100x from both sides to get 3000 = 300x, then divide both sides by 300 to see that x=10