How does -40 degrees Celsius equal -40 degrees Fahrenheit?

Answer 1

If you want to find the temperature where the Celsius and Fahrenheit are the same, simply

1) write out the equation that relates them

2) substitute C for F, or F for C. What you are doing is saying they are the same.

3) Solve.

The result will be the temperature at which Celsius and Fahrenheit are equal. I'm assuming that the answer is -40 degrees, but only because your question suggests it is. You can follow my above instructions to prove that out. If, however the answer is not -40 then the question is a trick question.

Answer 2

The Fahrenheit and Celsius scales meet at -40 degrees. This is because the two scales have different starting points (0 degrees for Celsius and 32 degrees for Fahrenheit) and different-sized units. The exact mathematical relationship is: (C × 9/5) + 32 = F, so when C = -40, (-40 × 9/5) + 32 = -40.