The ratio of family cars to the total number of cars on display in Ken's car shop was 3 : 8. ²₅ of the remaining cars on display were sports cars and the rest were saloon cars and electric cars in the ratio of 4 : 3. If there were 72 more family cars than saloon cars, how many electric cars were there?

Family Cars	Sports Cars	Saloon Cars	Electric Cars	Total Cars
3x7	5x7			8x7
	2x7	3x7		5x7
		4x3	3x3
21 u	14 u	12 u	9 u

The total number of saloon cars and electric cars is the combined repeated identity. Make the total number of saloon cars and electric cars the same. LCM of 3 and 7 is 21.

The total number of sports cars, saloon cars and electric cars is the next combined repeated identity. Make the total number of sports cars, saloon cars and electric cars the same. LCM of 5 and 5 is 35. 

Number of more family cars than saloon cars
= 21 u - 12 u
= 9 u

9 u = 72

1 u = 72 ÷ 9 = 8

Number of electric cars
= 9 u
= 9 x 8
= 72

Answer(s): 72