ACT math averages practice

What is the average of 10, 20, and 30?

Average = (10 + 20 + 30) / 3 = 20.

True or false: The average is always a number between the smallest and largest values.

True, because the average pulls values closer to a central point.

Fill in the blank: The average of 5, 15, and 25 is ____.

Average = (5 + 15 + 25) / 3 = 15.

Difference between mean and median.

Mean is the total divided by count; median is the middle value.

A store sells 4 shirts for $20 each. Average price?

Average price = Total cost / Number of shirts = $\displaystyle 80 / 4 =$20.

Calculate the average speed if a trip takes 3 hours covering 180 miles.

Average speed = Total distance / Total time = 180 miles / 3 hours = 60 mph.

True or false: An average can be determined from only two numbers.

True, because you can average any two values.

What is the average of 2, 4, 6, 8, and 10?

Average = (2 + 4 + 6 + 8 + 10) / 5 = 6.

If John earns $\displaystyle 300,$400, and $500 this month, what is his average paycheck?

Average paycheck = ($\displaystyle 300 +$400 + $\displaystyle 500) / 3 =$400.

In a class of 5 students with scores 70, 80, 90, 85, 75, find the average.

Average score = (70 + 80 + 90 + 85 + 75) / 5 = 80.

What affects the average: outliers or typical values?

Outliers significantly affect the average, pulling it away from central values.

Average of 12, 18, and 24?

Average = (12 + 18 + 24) / 3 = 18.

Find the average monthly rent if $\displaystyle 1200,$1300, $1100 are paid.

Average rent = ($\displaystyle 1200 +$1300 + $\displaystyle 1100) / 3 =$1200.

What is the average of the first five prime numbers?

First five primes: 2, 3, 5, 7, 11. Average = (2 + 3 + 5 + 7 + 11) / 5 = 5.6.

True or false: The average can never be a decimal.

False, averages can be decimals, e.g., 5.5.

Calculate the average of 100, 200, 300.

Average = (100 + 200 + 300) / 3 = 200.

If 4 numbers are 8, 12, 16, 20, what's the average?

Average = (8 + 12 + 16 + 20) / 4 = 14.