C= 5/9 (f-32)
For an experiment, a liquid is kept in cold storage at a temperature of 20 degrees Fahrenheit. The liquid is removed from cold storage and is warmed at a constant rate of 3 degrees Fahrenheit per hour. Which of the following represents the temperature of the liquid, in degrees Celsius, t hours after it has been removed from cold storage.
A) (5/3)t – 20/3
B)(5/3)t -188/9
C) (5/9)t – 20/3
D)(27/5)t +68
E) 3t +20
First, do the easy part: write the expression for the temperature in Fahrenheit.
20 + 3t
That whole expression is the temperature in Fahrenheit after t hours, so we need to put that whole expression into the conversion to Celsius.