Description:

The correct answer is:

✅ -40°C = -40°F

Why?

The Celsius and Fahrenheit scales intersect at -40°, making them equal at this temperature.

Verification:
Use the conversion formula:

• C5=F−3295C​=9F−32​

Set C=FC=F:

• x5=x−329  ⟹  x=−405x​=9x−32​⟹x=−40

Why Not the Others?

40°C = 104°F (not equal).

0°C = 32°F (freezing point, but not equal).

Fun Fact: -40° is so cold that antifreeze fails and steel becomes brittle! ❄️🔧

Bonus: This is a classic trivia question—now you’ll never forget it! 🧠✨