The ratio of electric cars to the total number of cars on display in Ken's car shop was 4 : 11. ⁴₇ of the remaining cars on display were sports cars and the rest were saloon cars and family cars in the ratio of 5 : 2. If there were 143 more electric cars than saloon cars, how many family cars were there?

Electric Cars	Sports Cars	Saloon Cars	Family Cars	Total Cars
4x7	7x7			11x7
	4x7	3x7		7x7
		5x3	2x3
28 u	28 u	15 u	6 u

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

The total number of sports cars, saloon cars and family cars is the next combined repeated identity. Make the total number of sports cars, saloon cars and family cars the same. LCM of 7 and 7 is 49. 

Number of more electric cars than saloon cars
= 28 u - 15 u
= 13 u

13 u = 143

1 u = 143 ÷ 13 = 11

Number of family cars
= 6 u
= 6 x 11
= 66

Answer(s): 66