|A ∪ B ∪ C| = |C|
Given: A = 1 min, B = 2 min, C = 8 min, D = 11 min. Only 2 can cross at a time with 1 lamp. Pair walks at slower person’s speed.
Best (exam) strategy:
1) A + B cross → 2 min
2) A returns → 1 min
3) C + D cross → 11 min
4) B returns → 2 min
5) A + B cross → 2 min
Total time = 2 + 1 + 11 + 2 + 2 = 18 minutes
Answer: 18 minutes
Online Test Series, Information About Examination,
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Online Test Series, Information About Examination,
Syllabus, Notification
and More.
Commented Feb 06, 2021
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