Section PF.2 – Practice Problems

1. In June Brandon started a new job and worked a total of 140 hours.

a. In July he worked 182 hours, what is the absolute change and relative change?

b. In August he worked 133 hours, what is the absolute change and relative change from June?

c. In September he worked 112 hours, what is the absolute decrease and relative decrease from June?

2. The population of a town increased from 3,850 in 2005 to 5,900 in 2012. By what percent (relative change) did the population increase?

3. The price of a latte dropped from $3.12 to $3.00. Find the absolute change and relative change of the price of a latte.

4. Theresa’s annual income increased from $31,000.00 to $48,000.00. Find the absolute change and relative change of Theresa’s annual income.

5. The tuition at a private college is increasing from $50,000.00 to $55,000.00.

a. Find the absolute change in tuition.
b. Find the relative change in tuition.
c. Which answer is more meaningful to your household budget?

6. A shirt that was originally marked as $24.95 rings up at the register as $19.96. What is the percent discount (relative change) on the shirt?

7. The U.S. Weather Bureau has a station on Mauna Loa in Hawaii that has measured carbon dioxide levels since 1959. At that time, there were 307 parts per million of carbon dioxide in the atmosphere. In 2005, the figure was 391 parts per million. Find the increase in carbon dioxide levels and the percent of increase. Round to the nearest tenth of a percent.

8. Anthony and his son Johnny are exercising more regularly and keeping track of their weight loss. Both Anthony and Johnny lost 10 pounds.

a. From this information alone, can you determine if they both lost the same percentage of weight?

b. Suppose Anthony’s starting weight is 190 pounds and Johnny’s starting weight is 155. Who lost a larger percent of their starting weight?

9. You received a coupon from your favorite furniture store in your email. The end table that you want is originally priced at $199.99. The coupon is for $25 off. What is the relative decrease? Round to the nearest tenth.

10. There were 160 M & M’s in the container yesterday, but now there are 116, what is the percent change?

11. Your credit card company called to notify you that the interest rate on your credit card will increase from 16% to 18%.

a. Determine the percentage points the interest rate will increase by.
b. Determine the percent increase of the interest rate.

12. Your credit card company called to notify you that the interest rate on your credit card will increase from 12% to 15%.

a. Determine the percentage points the interest rate will increase by.
b. Determine the percent increase of the interest rate.

13. The interest rate on your credit card is 5% and the credit card company has notified you that your rate will go up by 10 percentage points. What will your new interest rate be?

14. The interest rate on your credit card is 5% and the credit card company has notified you that your rate will go up by 10%. What will your new interest rate be?