Percent Change, Error, Interest Practice

The temperature in one day goes from 10^o to 15^o. What is the percent change?

• 50% increase

• 50% decrease

• 33% increase

• 33% decrease

Mrs. Tagliaferro had 27 students in her class last year and this year she had 30 students in her math class. What is the percent of change?

• 24%

• 20%

• 11%

• 50%

A microwave originally costs $96, but is marked up to a price of $115.20. What is the percent increase?

• 20% Increase

• 17% Increase

• 20% Decrease 

• 17% Decrease

Sally went to the clearance rack at a department store and found a shirt she wanted to buy.  The shirt was $36.00 and is on sale for $24.00.  What is the decrease in price?

• 33%

• 67%

• 50%

• 34%

Karen invested $800 in a savings account that earns an annual simple interest rate of 4%. She keeps the money in the account for 2 years.

Find the amount of interest she will earn.

• $64

• $6,400

• $32

• $3,200

Change 9.25% to a decimal.

• 9.25

• 925

• 0.925

• 0.0925

Mark’s grade on the first math exam was 94. His grade on the second math exam was 87.

What was the percent of change in Mark’s grade? Round your answer to the nearest whole percent?

• 108%

• 93%

• 8%

• 7%

What is the amount of the discount on this sweatshirt?

• $19

• $95

• $57

• $51

Brian needs to borrow $975 from the bank. He will have to pay 4.5% simple interest. Brian will pay back the loan in 4 years.

What is the total amount of money that he will need to pay back?

• $799.50

• $175.50

• $983.50

• $1150.50

Garrett was asked to guess how many marbles are in a jar.

He guessed that there were 615 marbles.

There were actually 750 marbles.

Find the percent error in this guess.

• 82%

• 135%

• 18%

• 22%