Percents
What is 25% of 80?
20
A bicycle originally cost $300 but is now on sale for $225. What is the percent decrease?
25% decrease
What is the simple interest on $500 at 4% annual interest for 3 years?
$60
A map has a scale of 1 inch = 5 miles. If two cities are 3 inches apart on the map, how far are they in real life?
15 miles
How can you tell if a graph is proportional?
Straight line and goes through the origin.
A student scores 18 out of 24 on a test. What percent did they score?
75%
A town’s population increased from 8,000 to 9,200. Find the percent increase.
15% increase
Find the simple interest on $800 at 6% annual interest for 2 years.
$96
If two rectangles are similar and the smaller one has a width of 5 inches while the larger one has a width of 15 inches, what is the scale factor?
3
The equation for a proportional relationship is y=2.5x. What is the constant of proportionality?
2.5
40% of what is 50?
125
A store has a 40% off sale. If an item originally costs $50, what is the sale price?
$30
If you invest $1,200 at 5% interest for 4 years, how much interest do you earn?
$240
A flagpole casts a 12-foot shadow at the same time a 6-foot tree casts a 2-foot shadow. How tall is the flagpole?
36 feet
If a point on a proportional graph is (2, 15), what is the constant of proportionality?
7.5
There are 320 hot dogs at a BBQ. 40% of the hot dogs have mustard on them. How many do not have mustard on them?
192 hot dogs
The predicted weight of a package was 4.2 pounds, but the actual weight was 3.8 pounds. Find the percent error to the nearest hundredth.
10.53%
A loan of $2,500 earns $375 in interest over 5 years. What is the interest rate?
3%
A building casts a shadow 30 feet long while a 5-ft-tall person casts a shadow 3 feet long. How tall is the building?
50 feet
The equation of a proportional relationship is given as 5y=20x. Find the constant of proportionality.
4
There are 20 cheerleaders in afterschool. If 25% of the after school students are in cheerleading, how many students are in after school?
80 students
A scientist predicts a temperature of 25°C, but the actual temperature is 28°C. What is the percent error to the nearest hundreth?
10.71%
A savings account earns 3% interest per year. If you deposit $2,000 and leave it for 7 years, how much interest will you earn?
$420
A model car has a scale of 1 in:20 ft. If the actual car is 15 feet long, how long is the model?
0.75 feet
A graph of a proportional relationship passes through (5,10). What is the equation of the line?
y = 2x