At what tempreature farenhite scale and celcius scale show the same reading

-40°F = - 40°C

Explanation:

To convert Celsius to Fahrenheit, the following equation is used:

F = 1.8C + 32

When the temperature on the Fahrenheit scale is the same on the Celsius scale, that means F = C. Substituting:

C = 1.8C + 32

0 = 0.8C + 32

-0.8C = 32

C = - 40

Therefore - 40°F = - 40°C.