Question

convert a variable number of days n to years. write an expression for the unit conversion. n days = \frac{n days}{1} \cdot \frac{1 yr}{\square days}=\square yr

Explanation:

Step1: Recall number of days in a year

We know that 1 year has 365 days (ignoring leap - years for simplicity). So the conversion factor is $\frac{1\ yr}{365\ days}$.
$n$ days $=\frac{n\ days}{1}\cdot\frac{1\ yr}{365\ days}$

Step2: Simplify the expression

When we multiply $\frac{n\ days}{1}\cdot\frac{1\ yr}{365\ days}$, the "days" units cancel out, and we get $\frac{n}{365}$ yr.

Answer:

$n$ days $=\frac{n\ days}{1}\cdot\frac{1\ yr}{365\ days}=\frac{n}{365}$ yr