January 22nd Teaser Solution

Brain Teasers: A brain teaser is a form of puzzle that requires thought to solve. It often requires thinking in unconventional ways with given constraints in mind; sometimes it also involves lateral thinking. Logic puzzles and riddles are specific types of brain teasers. Today's can be found below....

The Teaser

1. Inside the drawer of a dressing-table in a dark room, there are 28 black socks and 28 brown socks. What is the minimum number of socks that I must take out of the drawer to guarantee that I have a matching pair?

2. Timothy and Urban compete in a car rally, going several times around a closed circuit. Timothy can drive the circuit in 25 minutes, but Urban takes 30 minutes. If the two drivers start at the same time, how long will it take Timothy to lap Urban?

The Solution

1. Three. If I pick three socks, then either they are all of the same color in which case I certainly have a pair of the same color] or else two are of one color and the third is of the other color, so in that case I would again have a matching pair.

2. 25 minutes after starting Timothy finishes the first lap and Urban has only driven 25/30 of the circuit, or 5/6. Hence Timothy gains 1/6 lap on Urban every 25 minutes. He laps Urban in 6 X 25 minutes = 150 minutes - that is, 2 1/2 hours.

 Today's Puzzles: