Replacing <em>F</em> with <em>F</em> + 1 gives
5/9 (<em>F</em> + 1 - 32) = 5/9 (<em>F</em> - 32) + 5/9 = <em>C</em> + 5/9
so a temperature increase of 1º F translates to a 5/9º increase in Celsius, so I is true.
Replacing <em>F</em> with <em>F</em> + 5/9 gives
5/9 (<em>F</em> + 5/9 - 32) = 5/9 (<em>F</em> - 32) + (5/9)² = <em>C</em> + 25/81
so increasing the temperature by 5/9º F amounts to a 25/81º increase in Celsius, so III is false.
Solve for <em>F</em> in terms of <em>C</em> :
<em>F</em> = 9/5 <em>C</em> + 32
Replacing <em>C</em> with <em>C</em> + 1 gives
9/5 (<em>C</em> + 1) + 32 = 9/5 <em>C</em> + 32 + 9/5 = <em>F</em> + 9/5
and 9/5 = 1.8, so a 1º C increase translates to a 1.8º F increase, so II is also true and the answer is D.
Answer: eastward westward north and south clockwise.
