Answer:
They would have built 84 cars
Step-by-step explanation:
From the question, they have already built 9 cars
Now, the hourly production rate is 15 cars per hour;
So therefore, in 5 hours, total that would have been built excluding the initial 9 will be;
15 * 5 = 75 cars
Now, let us add the initial 9
we have this as 9 + 75 = 84 cars
