AlgebraMediumRate of change from two readings
Algebra practice question
At 6 a.m. the temperature was 68°F, and at noon it was 86°F. If the temperature rose at a constant rate, by how many degrees Fahrenheit did it rise each hour?
Answer: 3
The rise is 86 − 68 = 18 degrees over 12 − 6 = 6 hours, so the rate is 18 / 6 = 3 degrees per hour.
Common wrong answers
- If you answered 6
- 6 is the number of hours, not the rate.
- If you answered 18
- 18 is the TOTAL rise from 6 a.m. to noon. Divide by the 6 hours to get the rate.
- If you answered 0.33
- 0.33 is 6 / 18, the ratio upside down. Rate is degrees PER hour: 18 / 6.
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