①
% of all toys that were dolls and teddy bears

= 100% - 30% = 70%

②
Since the ratio of dolls to teddy bears is 4 : 1, total number of units for dolls and teddy bears

= 4 + 1 = 5

So 70% of all toys = 5 units

1 unit = 70% of all toys ÷ 5
= 14% of all toys

Number of dolls = 4 units
= 14% of all toys x 4
= 56% of all toys


③
Difference in number of dolls and toy cars

= 56% of all toys - 30% of all toys
= 26% of all toys

Since there are 156 more dolls than toy cars,

156 toys = 26% of all toys
1% of all toys = 156 toys ÷ 26
= 6 toys

④
Number of toys that were dolls and teddy bears = 70% of all toys
= 70 x 6 toys
= 420 toys


⑤
No teddy bears and dolls were sold. Their number remained the same.

If toy cars were 16% of all remaining toys, % of all remaining toys that were dolls and teddy bears

= 100% - 16% = 84%

So 84% of all remaining toys = 420 toys

1% of all remaining toys
= 420 toys ÷ 84
= 5 toys

Number of toy cars left in the shop
= 16% of all remaining toys
= 16 x 5
= 80

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