Percentages
What is 25% of 80?
20
Solve for x: x + 7 = 15
x = 8
A bag has 3 red marbles and 7 blue marbles. What is the probability of picking a red marble?
3/10 or 30%
What is the absolute value of −9?
9
A recipe uses 2 cups of flour for every 3 cups of sugar. How much sugar is needed for 6 cups of flour?
9 cups of sugar
A shirt costs $40. It is on sale for 15% off. What is the sale price?
$34
Solve for y: 3y − 4 = 11
y = 5
A number cube is rolled. What is the probability of rolling an even number?
3/6 = 1/2 or 50%
Order from least to greatest: −3, 1.5, −7, 0, 4
−7, −3, 0, 1.5, 4
A map has a scale of 1 inch = 50 miles. Two cities are 3.5 inches apart on the map. How far apart are they in real life?
175 miles
A student got 18 out of 24 questions correct on a test. What percent did she get correct?
75%
Write an inequality for: 'A number n is at least 12.'
n ≥ 12
A coin is flipped twice. List all possible outcomes in the sample space.
HH, HT, TH, TT (4 outcomes)
Is −5 a rational number? Explain.
Yes — it can be written as −5/1, a ratio of two integers
Are the ratios 4:6 and 10:15 proportional? Show how you know.
Yes — 4/6 = 2/3 and 10/15 = 2/3
A store marks up a jacket 40% from its original cost of $65. What is the selling price?
$91
Solve and graph on a number line: 2x + 3 < 11
x < 4 (open circle at 4, arrow pointing left)
A spinner has 4 equal sections: red, blue, green, yellow. What is the probability of NOT landing on red?
3/4 or 75%
Evaluate: −12 + (−8) − (−5)
−15
A scale drawing of a room uses 1 cm = 2.5 m. The room is 6 cm × 4 cm on the drawing. What are the actual dimensions?
15 m × 10 m
After a 20% discount and then an additional 10% discount, what is the total percent discount off the original price?
28%
Solve for x: (x/3) + 5 = 9
x = 12
A bag has 5 red, 3 blue, and 2 green marbles. What is the probability of picking red, then blue (without replacement)?
5/10 × 3/9 = 15/90 = 1/6
A submarine is at −240 feet. It rises 3/4 of the way to the surface. What is its new depth?
−60 feet
A car travels 240 miles in 4 hours. At the same rate, how long will it take to travel 390 miles?
6.5 hours