To determine the multiplier Katherine should use to find the price she would have to pay after applying a 3% discount, we first need to understand how discounts work.
A 3% discount means that she pays 97% of the original price. This is because:
\[ 100% - 3% = 97% \]
To express 97% as a decimal for calculations, we convert it by dividing by 100:
\[ 97% = 0.97 \]
Thus, Katherine should multiply the original price by 0.97 to find the price after the discount.
In summary, Katherine should multiply the prices on the tags by 0.97 to find the price she would have to pay, before tax.