What is the temperature reading on the Fahrenheit scale such that it is five times the reading on the Celsius scale?

Let the reading on the celsius scale be x

$\therefore$ The Fahrenheit scale(F) is five times that of the Celsius scale(C). This implies that we can write

 $F=5x$

The relation between the temperature of an object in centigrade and Fahrenheit is given as:
$\frac{C}{5}=\left(\frac{F-32}{9}\right)$
 

$\frac{x}{5}=\frac{(5x-32)}{9}$

$9x=25x-160$
$160=16x$
Reading of $x={10}^{0}C$
(i) Celsius scale $={10}^{0}C$
(ii) Fahrenheit scale $=5x = {50}^{0}F$