Finding a percentage of a total amount: Real-world situations

In this lesson, we solve problems on finding a percentage of a total amount in real-world situation.

Consider the following solved examples.

A plant was 53 centimeters tall. After a month, it had grown 8% taller. How tall was the plant after a month?

Solution

Step 1:

The original height of the plant = 53 cm

percentage increase in height = 8 %

Step 2:

Increase in the height of the plant = 8% of 53 cm = 0.08 × 53 = 4.24 cm

Height of the plant after increase = 53 cm + 4.24 cm = 57.24 cm

A furniture store had a chair that cost $38. After a few months, the owner took 12% off the price. How much is the chair now?

Solution

Step 1:

The original price of the chair = $38

percentage discount in price = 12 %

Step 2:

Discount in price of chair = 12% of $38 = 0.12 × $38 = $4.56

Price of the chair after discount = $38 −$ 4.56 = $33.44

A store was selpng lawn mowers for $67. The repair agreement is 21 percent of the price of the mower. How much would it cost for a mower and repair agreement?

Solution

Step 1:

The price of the lawn mower = $67

Repair agreement percent = 21 %

Step 2:

Repair agreement cost = 21% of $67 = 0.21 × $67 = $14.07

Cost of lawn mower and repair agreement = $67 + $14.07 = $81.07