Final answer:
Alex earned $1,100 last week by selling cars. He has a base salary of $500 and earns $150 per car sold. By creating an equation and solving for the number of cars, it's calculated that Alex sold 4 cars last week.
Step-by-step explanation:
To determine how many cars Alex sells, we need to use the information provided about his earnings. Alex earns a base salary of $500 per week plus an additional $150 for each car sold. If he earned $1,100 last week, we can set up an equation to find out the number of cars sold. $500 + ($150 × number of cars sold) = $1,100. First, subtract the base salary from the total earnings to find the earnings from the cars sold: $1,100 - $500 = $600. Next, divide the earnings from car sales by the amount earned per car to find the number of cars: $600 / $150 = 4 cars. Therefore, Alex sold 4 cars last week.