Final answer:
To find the original price of the T-shirt before the 20% discount, set up an equation using the given information and solve for 'x'.
Step-by-step explanation:
To find the original price before the 20% discount, we can set up an equation.
Let 'x' represent the original price.
After a 20% discount, the price is 100% - 20% = 80% of the original price. So we have 80% of 'x' equals $24.
Using this information, we can write the equation: 0.8x = $24. Solving for 'x', we find that the original price of the T-shirt was $30.
Learn more about Finding the original price before a discount on an item