Question

At what temperature, due the Celsius and Fahrenheit scales show then same reading but with opposite sign?

• A. 11.44
• B. 20
• C. 40
• D. 10

Answer 1

The correct option is C 40

${}^{\circ }F={}^{\circ }C\times \frac{9}{5}+32$

${}^{\circ }C=\left({}^{\circ }F-32\right)\times \frac{5}{9}$

$C=C\times \frac{9}{5}+32$ $\left[F=C\right]$

$C-\frac{9C}{5}=32$

$C=-40$

( So at ${40}^{\circ }C$ they give same reading)