A math test ended at 3:55 and it took 50 minutes to complete. What time did the math test start?
The math test started at 3:05.
If we know that the math test ended at 3:55 and lasted 50 minutes, we can subtract 50 minutes from 3:55 and we will get an answer of 3:05.
Therefore, the math test started at 3:05.