Question

At what temperature Celsius and Fahrenheit are equal?

• A. $-{25}^{\circ }C$
• B. $-{35}^{\circ }C$
• C. $-{40}^{\circ }C$
• D. $-{30}^{\circ }C$

Answer 1

The correct option is C $-{40}^{\circ }C$

Fahrenheit and Celsius are measurements of temperature and are related to each other as follows:
$C=(F-32)\times \frac{5}{9}$
Where C is the temperature in Celsius and F is the temperature in Fahrenheit.

Since we need temperature and celsius to be equal:
Now, let $C=F=x$
So,
$x=(x-32)\times \frac{5}{9}$
$\Rightarrow 9x=5x-160$
$\Rightarrow 4x=-160$
$\Rightarrow x=-40$

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

Thus at $-{40}^{\circ }C$ temperature, Celsius and Fahrenheit are equal.