Multiple choice

Directions: Read the following information and answer the given question.

Four friends A, B, C and D need to cross a bridge. A maximum of 2 persons can cross at a time. It is night and they have just 1 lamp. Persons actually crossing the bridge must carry the lamp to see the way. A pair must walk together only at the speed of the slower person. The speeds are: A: 1 minute to cross the bridge B: 2 minutes to cross the bridge C: 7 minutes to cross the bridge D: 10 minutes to cross the bridge

What is the total minimum time required for all the 4 friends to cross the bridge?

  1. 15 minutes

  2. 17 minutes

  3. 21 minutes

  4. 23 minutes

  5. 25 minutes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A and B go across. A stays and B comes back. Time spent = 4 minutes C and D go across. Time spent = 10 minutes Total time spent = 14 minutes Now A goes across and gets B. Time spent = 3 minutes  Total time spent = 17 minutes

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