A Celsius scale and a Fahrenheit scale give exactly the same number at one temperature. What is that number?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → −40
The scales are related by \(F=\frac{9}{5}C+32\). Putting F = C gives \(C-\frac{9}{5}C=32\), so \(-\frac{4}{5}C=32\) and C = F = −40.