AlgebraMediumTemperature where two scales agree
Algebra practice question
Temperatures in degrees Celsius, C, and degrees Fahrenheit, F, are related by F = 1.8C + 32. At what temperature, in degrees Celsius, do the two scales give the same reading?
Answer: -40
Set F = C: C = 1.8C + 32 → −0.8C = 32 → C = −40.
Common wrong answers
- If you answered 40
- 40 has the wrong sign: −0.8C = 32 gives a negative C.
- If you answered -17.8
- −17.8 is 0°F in Celsius, not where the scales agree.
- If you answered -160
- −160 comes from 0.2C = −32, subtracting 1.8 from 2 instead of from 1.
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