Answer:
The next two times both buckets dump water at the same time are 4:54 P.M and 7:18 P.M.
Explanation:
From the question, one bucket dumps water every 18 minutes, say bucket A;
and the other bucket dumps water every 16 minutes, say bucket B.
Also, It is currently 2:45 P.M. and both buckets dumped water 15 minutes ago,
that is, both buckets dumped water at 2:30 P.M.
For bucket A, the next times it will dump water will be:
2:48 P.M, 3:06 P.M, 3:24 P.M, 3:42 P.M, 4:00 P.M, 4:18 P.M, 4:36 P.M, 4:54 P.M, 5:12 P.M, 5:30 P.M, 5:48 P.M, 6:06 P.M, 6:24 P.M, 6:42 P.M, 7:00 P.M, 7:18 P.M, 7:36 P.M, 7:54 P.M, 8:12 P.M, 8:30 P.M etc.
For bucket B, the next times it will dump water will be:
2:46 P.M, 3:02 P.M, 3:18 P.M, 3:34 P.M, 3:50 P.M, 4:06 P.M, 4:22 P.M, 4:38 P.M, 4:54 P.M, 5:10 P.M, 5:26 P.M, 5:42 P.M, 5:58 P.M, 6:14 P.M, 6:30 P.M, 6:46 P.M, 7:02 P.M, 7:18 P.M, 7:34 P.M, 7:50 P.M etc.
From above, we observe that the next two times both buckets dump water at the same time are 4:54 P.M and 7:18 P.M.
Hence, the next two times both buckets dump water at the same time are 4:54 P.M and 7:18 P.M.