Problem 8 · 2009 Math Kangaroo
Medium
Logic & Word Problems
off-by-one
A certain film lasts 90 minutes. It begins at 17:10. During the film there are two advert breaks, one lasting eight minutes and the other five minutes. At what time will the film end?
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Answer: D — 18:53
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Hint 1 of 2
Add the film length and both break lengths to the start time.
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Hint 2 of 2
Work in minutes from 17:10.
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Approach: add all the durations to the start time
- The film runs 90 minutes and the breaks add 8 + 5 = 13 minutes.
- Total time on screen and breaks: 90 + 13 = 103 minutes.
- Starting at 17:10, add 103 minutes: 17:10 + 1 h 43 min = 18:53.
- So the film ends at 18:53.
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