Logic: use logic and math to solve these puzzles.

Four people need to cross a rickety bridge at night. They have only one flashlight, and the bridge can only hold two people at a time. It’s too dangerous to walk without a light. The four people all walk at different speeds: one can cross the bridge in 1 minute, another in 2 minutes, another in 5 minutes, and the slowest in 10 minutes. When two people cross the bridge together, they must go at the slower person’s pace. What’s the shortest time it takes all four to get across the bridge?

[expander_maker id=”1″ more=”Show Answer” less=”Hide Answer”]Answer: 19 minutes ( 2 + 5 + 10 = 17 minutes is incorrect, as it doesn’t account for the time the faster person returns with the flashlight to escort their friend across; the correct answer is 2 + 1 + 5 + 1 + 10 = 19 )[/expander_maker]