Which temperature represents 25 degree Celsius (°C) in degrees Fahrenheit (°F)?

Let $t_u$ be the time Mario takes to walk up the hill and $t_d$ be the time he takes to skateboard down the hill.
Let $v_u$ be his speed walking up the hill and $v_d$ be his speed skateboarding down the hill.
The distance of the hill, $D$, is the same for both directions.
We know that $D = v_u t_u$ and $D = v_d t_d$.
We are given that Mario can skateboard down a hill three times faster than he can walk back up, so $v_d = 3v_u$.

To convert temperature from degrees Celsius ($^\circ\text{C}$) to degrees Fahrenheit ($^\circ\text{F}$), use the formula: