V-neck shirts regularly cost $15.00 each. This week, a v-neck shirt is 30% off. What is the sale price?

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