A group of 4 people has to cross a bridge. It is dark, and they have to light the path with a flashlight. No more than 2 people can cross the bridge simultaneously, and the group has only one flashlight. It takes different time for the people in the group to cross the bridge:

Annie crosses the bridge in 1…

**Best Answer:** Solution:

We shall list the solution in the first column, the time required for each task in the second column, and a running count of the time in the right column.

Action…….Time Required……..Running Time

1. Bob and Annie cross. 2 minutes…2 minutes

2. Bob comes back across alone. 2 minutes…4 minutes

3. Sherlock and Dorothy cross. 10 minutes…….14 minutes

4. Annie comes back across. 1 minute….15 minutes

5. Annie and Bob head back across. 2 minute….17 minutes