Question

At what temperature do Celsius and Fahrenheit scales coincide?

• A. -30 degrees
• B. -40 degrees
• C. -20 degrees
• D. -10 degrees

Answer 1

The correct option is B -40 degrees

Using temperature scale conversions,
$C=\frac{5}{9}(F-32)$
Given, $C=F$
$⟹C=\frac{5}{9}(C-32)$
$C=-40$

$\therefore -{40}^{\circ }C=-{40}^{\circ }F$