The temperature at which the reading of a Fahrenheit thermometer will be double that of a Centigrade thermometer is :

Given,

Fahrenheit thermometer will be double that of a Centigrade thermometer is $F=2C$

The relation between the temperature of an object in centigrade and Fahrenheit is given as:

$\frac{C}{100}=\frac{F-32}{180}$

$\frac{C}{100}=\frac{2C-32}{180}$
$C\times 9=5(2C-32)$
 

$9C=10C-160$
$C={160}^{0}C$ 

Therefore, 160^o C is the correct response.