Question

At what temperature is the Celsius and Fahrenheit equal, if the relation between Celsius and Fahrenheit is
$\frac{F-32}{9}=\frac{C}{5}$

• A. ${40}^o$
• B. $-{40}^o$
• C. $0^o$
• D. ${100}^o$

Answer 1

The correct option is B

$-{40}^o$

We use relationship $\frac{F-32}{9}=\frac{C}{5}$. We substitute both F and C as 'X' in the relationship equation as Celsius and Fahrenheit are equal according to question.
On solving the equation,
$\frac{X-32}{9}=\frac{X}{5}$
$\Rightarrow 5X-160=9X$
$\Rightarrow -4X=160orX=-40$