Hello!
We know that you sell each toy car for $36.00 and you've made 24 so far.
Multiply the price of each car by how many you've made so far.
36 × 24 = 864
This means you'll make $864.00 when you sell 24 cars.
Since you want to earn $1620.00 and you've already got $864.00 of it, subtract the money you'll get from 24 cars from how much money you want to earn.
1,620 - 864 = 756
Finally, divide this by the cost of each car.
756 ÷ 36 = 21
So, you'll have to build and sell 21 more cars to earn $1,620.00.