A family travels to Bryce Canyon for three days. On the first day, they drove 140 miles. On the second day, they drove 200 miles. What is the least number of miles
they drove on the third day if their average number of miles per day was at least
180?

A family travels to Bryce Canyon for three days. On the first day, they drove 140  miles. On the second day, they drove 200 miles. What is the least number of miles  they drove on the third day if their average number of miles per day was at least  180?

To find the average number of something, you would take all of the numbers you want to find the average of, add them together, and divide by the total number of items you added up.

For example: in this question, you have 140 miles, 200 miles, and x miles (the amount of miles they drove on the third day).

You would add all of these miles together and divide by 3, since you added 3 numbers together. This would equal the average.

Finding the average:  

Create an equation where all of the miles they drove are added together, divide this expression by 3, and set this greater than or equal to 180 (since they drove at least 180 miles on average).

Solve for x to find the least number of miles they drove on the third day. Multiply both sides by 3.

Combine like terms on the left side of the equation.

Subtract 340 from both sides of the equation.

The least number of miles the family drove on the third day was 200 miles, since x can't be anything less than 200.

x+14

step-by-step explanation: