Answer:
The time interval between the events in S its zero, and in S' its 4 min.
Explanation:
The space-time interval its defined as:
(of course, using the (+ - - -) metric signature).
In the inertial frame S, the events are separated by 3 light - minutes in space, and occur at the same instant in time, so:
In the inertial frame S', the events are separated by 5 light - minutes in space, and we don't know how far are they separated in time, so:
.
Now, between inertial frames the spacetime interval for the same events must be constant. So:
So, in the S' inertial frame, the time interval its 4 min.