There are several ways in which you could calculate this time period.
One would be to "borrow" in 8:10 p.m." 7:70.
From 7:70 you'd subtract 2:16 pm, obtaining 5:54 (hours)
Last, add 12 hours, since we're going from 2:16 a.m. to 2:16 p.m. (12 hours) and then from 2:16 p.m. to 8:10 p.m. (5:54 hours).
Total time elapsed: 17:54 (17 hours 54 minutes)
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The Europeans have it a bit easier, as they use 24-hour time.
8:10 for them would be 20:10; for the purpose of our problem solving that would be 19:70. Subtracting 2:16, we'd get 17:54 (17 hours, 54 minutes).