1. [5] The formula to convert Celsius to Fahrenheit is
$$
F^{\circ}=1.8 \cdot C^{\circ}+32 \text {. }
$$

In Celsius, it is $10^{\circ}$ warmer in New York right now than in Boston. In Fahrenheit, how much warmer is it in New York than in Boston?
Answer: $18^{\circ}$
Solution: Let $x$ and $y$ be the temperatures in New York and Boston, respectively, in Fahrenheit. Then $x-y=10$, so we compute
$$
(1.8 \cdot x+32)-(1.8 \cdot y+32)=1.8 \cdot(x-y)=18 \text {. }
$$