Answer:
The maximum number of days for the trip
Explanation:
Given
--- Missing Equation
Required
What does d represent?
From the question, we understand that t represent the number of days;
So, by default 212 represent days
Going further:
For the equation, to be valid; the value of t must be within the interval;
When
that is the beginning of the journey
As t increases;
212 - t decreases
Until the point where t = 212,
This signifies the end of the journey
So: 212 - t indicates a particular day between 0 and 212.
Hence, 212 represents the maximum number of days for the trip.