Answer:
80 toy cars were left in the shop.
Explanation:
Since there were toy cars, dolls and teddy bears in a shop, and 30% of the toys were toy cars, and the ratio of the number of dolls to the number of teddy bears were 4: 1, and there were 156 more dolls than toy cars, and after some toy cars were sold, 16% of the remaining toys in the shop were toy cars, to determine how many toy cars were left in the shop the following calculation must be performed: 
 
Toy cars = 30% 
Dolls and teddy bears = 70% 
70/5 = 14 x 4 = 56 
Dolls = 56% 
Teddy bears = 14% 
56 - 30 = 26 
156/26 = 6 (1%) 
 
Toy cars = 30 x 6 = 180 
Dolls = 56 x 6 = 336 
Teddy bears = 84 
 
100 - 16 = 84 
 
84 = 336 + 84 = 420 
16 = X 
84 = 420 
16 = X 
16 x 420/84 = X 
80 = X 
 
Therefore, 80 toy cars were left in the shop.