Answer:
The observed temperature was 10º Celsius or 50º Fahrenheit.
Explanation:
The traveler observed that the temperature in Fahrenheit is five times the value of the temperature in Celsius, therefore:
[tex]F = 5*C[/tex]
A Fahrenheit temperature relates to a Celsius one by the following expression:
[tex]F = \frac{9}{5}*C + 32[/tex]
Using the second expression on the first, we can solve for the temperature in Celsius, this is done below:
[tex]\frac{9}{5}*C + 32 = 5*C\\\frac{9}{5}*C - 5*C = -32\\\frac{9*C - 25*C}{5} = -32\\\frac{-16*C}{5} = -32\\-16*C = -32*5\\-16*C = -160\\C = \frac{-160}{-16} = 10\º\text{C}\\F = 5*C = 5*10 = 50\º\text{F}[/tex]
The observed temperature was 10º Celsius or 50º Fahrenheit.