Explanation:

- The pipe fills the bucket in 3 hours. This means it fills 1/3 of the bucket in an hour.

- With a hole, the same bucket takes 5 hours to fill, so it fills 1/5 of the bucket in an hour.

- The difference in the filling rate is due to the leak, which means the leak empties 1/3 - 1/5 = 2/15 of the bucket per hour.

- To empty a full bucket, the rate is 2/15 of the bucket per hour.

- Therefore, the time to empty the bucket is the reciprocal of the leak rate: 15/2 = 7.5 hours.

Option:5 - 7.5 is the correct answer.