Question

The equation s = p - 0.15p represents the sale price s of an item with an original price p, after a 15% discount. A T-shirt costs $12. What is the sale price?

Answer 1

s = 12 - .15(12)
s = 12 - 1.80
s = $10.20

Check
If 15% comes off the price, then 85% of the price is left to pay. (100 - 15 = 85)

12 x .85 = $10.20

Answer 2

$10.20...plug in 12 for p and you get s = 12 - (0.15 × 12), which is equal to 12 - 1.8, or 10.2.