Answer: D.
This is tricky.
Think of the equation as an equation for a line
where in this case.
[tex]C=5/9(f-32)[/tex]
or
[tex]C=5/9f-5/9(32)[/tex]
You can see the slope of the graph is [tex]5/9[/tex] which means that for an increase of 1 degree Fahrenheit, the increase is [tex]5/9[/tex].
[tex]c=5/9(f)[/tex]
[tex]c=5/9(1)=5/9[/tex]
Therefore, statement I is true. This is the equivalent to saying that an increase of 1 degree Celsius is equal to an increase of [tex]9/5[/tex] Degrees Fahrenheit
[tex]c=5/9(f)[/tex]
[tex]1=5/9(f)[/tex]
[tex]f=9/5[/tex]
Since [tex]9/5=1.8[/tex] Statement 2, is true.
The only answer that has both statement I and statement II as true is D, but if you have time and want to be absolutely thorough, you can also check to see if statement III (an increase of [tex]5/9[/tex] degree Fahrenheit is equal to a temperature increase of 1 degree Celsius) is true:
[tex]c=5/9(f)[/tex]
[tex]c=5/9(5/9)[/tex]
[tex]c=25/81[/tex] which is ≠ 1)
An increase of [tex]5/9[/tex] degree Fahrenheit leads to an increase of [tex]25/81[/tex]
not 1 degree, Celsius, and so Statement III is not true.
The final answer is D.
I hope this helped x
