Answer:
d) By 33.3%
Explanations:
Given the original price of the pair of shoe to be $100. If the price increased by 50%, the new price is calculated as:

If the price is reduced by 50% due to falling price, the new price of the shoe will be:

This shows that the new price due to falling price is $75
To calculate the percent the shoes be decreased in order to have the price back at $100, we will use the expression below;

Solve for "x"

This shows that the shoes should have been decreased by 33.3% to have the price back at $100