The music can stop at any time within 1.5 minutes after starting. The probability needs to be found that the music stops within the first 15 seconds.
Total time: 1.5 minutes
1.5×60=90 seconds
First 15 seconds = 15 seconds
The music stops at any time within 90 seconds with equal probability (uniform probability).
Probability =Total time availableTime interval of interest
Probability =9015
9015=90÷1515÷15
=61
Therefore, the probability that the music will stop within the first 15 seconds is 61.