First, convert the 75% to a real mathematical number. For percents, this is always done by dividing the 75% by 100%, or 75% / 100% = 0.750.
Second, find out what 75% of $120 is. This is the amount of the sale discount. This is always found by mulitplying 0.750 by the item's cost $120, like this:
0.750 x $120 = $90.00.
So for this sale, you'll save $90.00 on this item.
This means, the cost of the item to you is
$120 - $90.00 = $30.00.
Alternatively, you can think about it this way. The item is 75% off. This means you'll pay 25.000% of the total cost (100% - 75% = 25.000%).
Now what's 25.000% of the total cost?
0.250 x $120 = $30.00.
Just like the result above, the sale price on the item is $30.00.
Hope this helps you! Brainliest? :)