Do two things have to start at exactly the same time to happen simultaneously could they start 10 seconds apart and still be considered to have happened simultaneously?

Answer 1

The concept of being simultaneous does not depend on when things start. For example, you could say that flooding was caused because snow was melting simultaneously with the arrival of rain. The snow might have started melting a week earlier, but what was important was that it was still going on at the same time as the rains came. For another example, the traffic jam was caused when a parade and the traffic of people leaving the football game reached the bridge simultaneously. It doesn't matter exactly when the football traffic or the parade started reaching the bridge; what matters is that the times when both kinds of traffic reached the bridge overlapped.