A faulty Celsius thermometer read 0.7degrees Celsius at melting point of pure ice and 99.5degrees Celsius at boiling point of water at normal pressure.

Question

What is the correct temperature when it reads 30 degrees Celsius

Answer 1

Ce is temp read

error = e = Ce - C
I assume error = e = m C + b
then
.7 = m(0) + b so b = .7
99.5 - 100 = -.5 = m(100) +.7

100 m = -1.2
m = -.012

at Ce = 30
e = 30 - C = -.012 C + .7
C-.012 C = 29.3
.988 C= 29.3
C = 29.7