Cogito

Technical Interview Questions

Posted in Uncategorized by qmarks on December 27, 2009

I was reading Heard on the Street: Quantitative Questions from Wall Street Interviews from Timothy Falcon Crack. You bet, I am preparing for summer job interviews. That book is the toughest one compared to Vault guides and Rotman CCC sample questions, especially the derivatives part.

With the permission of the author, I would like to share two pure quantitative and logic questions; email me if you can not find the answers (oyarar at gmail dot com)

Q1:your bedroom sock drawer contains eight red socks and eleven blue socks that are otherwise identical. the light is broken in your bedroom, and you must select your socks in the dark. what is the minimum number of socks you need to take out of your drawer and carry into your well-lit living room to guarantee that you have with you at least a matching pair to choose from.

Q2:there are 100 light bulbs lined up in a row in a long room. Each bulb has its own switch, and is currently switched off. The room has an entry door and an exit door. Each bulb is numbered consecutively from 1 to 100. Each stockbroker is numbered consecutively from 1 to 100. Broker number 1 enters the room, switches on every bulb and exits. Broker number 2 enters and flips the switch on every second bulb (turning off bulbs 2,4,6, …) Broker number 3 enters and flips the switch on every third bulb (changing the state on bulbs 3,6, 9, …) This continues until all 100 brokers have passed through the room.

How many of the light bulbs are illuminated after the 100th person has passed through the room and which light bulbs are they?
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