Percent Change and Percent Error
The Percent Proportion/Equation
Discounts, Markups, Tax, etc.
100
Find the percent change: 12 inches to 36 inches
200% increase
100
48 is 75% of what number?
64
100
A portable table tennis set costs $30 before a 30% discount. Find the sale price.
$21
200
Last week, you finished Level 2 of a video game in 32 minutes. Today, you finish Level 2 in 28 minutes. What is the percent of change?
12.5% decrease
200
What number is 0.4% of 40?
0.16
200
You are shopping for a video game system. At which store should you buy the system?
Store C
300
Find the percent change: 5/4 to 3/8
70% decrease
300
What number is 25% of 7/8?
7/32
300
A drone that costs $129.50 is discounted 40%. The next month, the sale price is discounted an additional 60%. Is the drone now “free”? If so, explain. If not, find the sale price.
$31.08
400
In one round of a game, you are asked how many bones are in a human body. If the percent error of your answer is at most 5%, you earn two points. If the percent error is at most 10%, but greater than 5%, you earn one point. You guess 195 bones. The correct answer is 206 bones. How many points do you earn?
1 point
400
20% of a number is x. What is 100% of the number? Assume x > 0.
5x
400
You buy a bicycle helmet for $22.26, which includes 6% sales tax. The helmet is discounted 30% off the selling price. What is the original price?
$30
500
Donations to an annual fundraiser are 15% greater this year than last year. Last year, donations were 10% greater than the year before. The amount raised this year is $10,120. How much was raised two years ago?
$8000
500
A quarterback completes 18 of 33 passes during the first three quarters of a football game. He completes every pass in the fourth quarter and 62.5% of his passes for the entire game. How many passes does the quarterback throw in the fourth quarter?
7
500
Samy wanted to save money to buy a tennis racket. In the first week, he saved 40% of the money needed for the racket. In the second week, he saved 3/4 of the remaining part of the money he needed. By then, there was a 5% increase in the price of the racket. As a result, he was still short $12. What was the original price of the racket?
$60