This thermometer reads 60° when the true temperature is 40°C. Calculate the value of X.

The ice point of an ungraduated mercury-in-glass thermometer is X, while its steam point is 90°. This thermometer reads 60° when the true temperature is 40°C. Calculate the value of X.

A. 60°
B. 48°
C. 40°
D. 30°

Correct Answer:

Option C = 40°