The ratio of saloon cars to the total number of cars on display in Ken's car shop was 4 : 7. ¹₃ of the remaining cars on display were sports cars and the rest were family cars and electric cars in the ratio of 4 : 3. If there were 400 more saloon cars than family cars, how many electric cars were there?

Saloon Cars	Sports Cars	Family Cars	Electric Cars	Total Cars
4x7	3x7			7x7
	1x7	2x7		3x7
		4x2	3x2
28 u	7 u	8 u	6 u

The total number of family cars and electric cars is the combined repeated identity. Make the total number of family cars and electric cars the same. LCM of 2 and 7 is 14.

The total number of sports cars, family cars and electric cars is the next combined repeated identity. Make the total number of sports cars, family cars and electric cars the same. LCM of 3 and 3 is 21. 

Number of more saloon cars than family cars
= 28 u - 8 u
= 20 u

20 u = 400

1 u = 400 ÷ 20 = 20

Number of electric cars
= 6 u
= 6 x 20
= 120

Answer(s): 120