Answer:
4:46
Explanation:
These are represented as times.
We can pretend as if the clock is going backwards
Time duration between 6:51 and 6:30 is 21 minutes
Time duration between 6:30 and 6:07 is 23 minutes
Time duration between 6:07 and 5:42 is 25 minutes
Time duration between 5:42 and 5:15 is 27 minutes
See the pattern? The time duration increases by 2 minutes at each interval
So the next time duration will be 29 minutes
And 29 minutes before 5:15 is 4:46
-Chetan K