Finding the final amount given the original amount and a percentage increase or decrease

In this lesson, we learn how to find a final amount, given an original amount and a percentage increase or decrease. The percentage increase may be a markup or profit or just increase in price. Similarly, the percentage decrease may be markdown or discount or loss.

Rules to find the final amount given the original amount and a percentage increase or decrease.

First consider the original amount.

Then consider the rate or percentage increase or decrease

To find the markup or discount, multiply the rate by the original amount.

To find the final amount, add or subtract the markup or discount from original amount.

The next model of a sports car will cost 6% more than the current model. The current model costs $4,000. How much will the price increase in dollars? What will be the price of the next model?

Solution

Step 1:

Current model price = $40,000

Percentage increase in price = 6%;

Step 2:

Price increase in dollars = 6% of $40,000 = 0.06 × 4000 = $2400

Next model price = current model price + increase in price

= $40,000 + $2,400

= $42,400

A store was selpng lawn chairs at a unit price of $48. The store further offered a 15% markdown on the price of the chair. How much would a chair now cost?

Solution

Step 1:

Price of lawn chair = $48

Markdown = 15% of $48 = 0.15 × 48 = $7.20

Step 2:

Price after discount = $48 – $7.20 = $40.80