First, we must find how much is 30% of the cost
30% cost = 30% × regular cost
30% cost = 30/100 × 15
30% cost = 450/100
30% cost = 4.5
Second, substract 30% of the cost from regular cost to find the sale price
sale price = regular - 30% of the cost
sale price = 15 - 4.5
sale price = 10.5
The sale price is $10.5
