1. If the original quantity is 10 and the new quantity is 13, what is the percent increase?
2. Craig likes to collect records. Last year he had 10 records in his collection. Now he has 12 records. What is the percent increase of his collection?
3. If the original quantity is 5 and the new quantity is 3, what is the percent decrease?
4. At noon, a tank contained 10 cm of water. After several hours, it contained 7 cm of water. What is the percent decrease of water in the tank?
5. Estimation Suppose the original quantity is 13 and the new quantity is 1.
a. Which of these is the best estimate for the percent change?
A. 50%
B. 25%
C. 100%
D. 75%
b. Is this an example of a percent increase or a percent decrease?
6. If the original quantity is 15 and the new quantity is 19, which of these is the best estimate for the percent change?
A. 50% increase
B. 100% decrease
C. 75% increase
D. 25% increase
7. Last year, the Debate Club had 7 members. This year there are 12 members in the club. Which of these is the best estimate for the percent change in the number of club members?
A. 25% increase
B. 100% decrease
C. 75% increase
D. 50% decrease
8. Jake ordered 23 large pizzas for a party. When the party was over he had 6 large pizzas remaining. Estimate the percent change in the number of large pizzas.
A. 100% decrease
B. 25% increase
C. 50% increase
D. 75% decrease
9.
a. Writing If the original quantity is 25 and the new quantity is 50, what is the percent increase?
b. Explain what operation is equivalent to finding this new quantity. Write the explanation as an expression.
10. Money A savings account increases from $250 to $270. What is the percent increase of the savings account?
11. Think About the Process Suppose the original quantity is 175 and the new quantity is 126.
a. What expression represents the percent decrease?
A. fraction 126 minus 175 , over 175 end fraction
B. fraction 175 minus 126 , over 175 end fraction
C. fraction 126 minus 175 , over 126 end fraction
D. fraction 175 minus 126 , over 126 end fraction
b. What is the percent decrease?