A car dealership has 240 cars in the parking lot and 17.5% of them are red of the other six colors in the lot. Each color has the same number of cars if one of the colors is black how many black cars are in the lot.
If 17.5% of the 240 cars are red, there are 0.175 * 240 = 42 red cars in the lot.
This means that the remaining 240 - 42 = 198 cars are one of the other six colors.
If each color has the same number of cars, then there are 198 / 6 = 33 cars of each color.
Since we know there are 42 red cars, that means there are 33 black cars in the lot.