To model the situation, we start by letting \( t \) represent the time of the bus ride in minutes. According to the problem:
- Tran's total travel time consists of the bus ride time plus the walking time. The walking time is given as 30 minutes.
- The total travel time is stated to be 4 times the bus ride time.
We can express the total travel time as:
\[ \text{Total Travel Time} = t + 30 \]
According to the problem, this total travel time is also equal to 4 times the bus ride time, which can be expressed as:
\[ \text{Total Travel Time} = 4t \]
Now we can set these two expressions for total travel time equal to each other:
\[ t + 30 = 4t \]
This equation models the situation described.