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Matt@VeritasPrep
- GMAT Instructor
- Posts: 2630
- Joined: Wed Sep 12, 2012 3:32 pm
- Location: East Bay all the way
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- GMAT Score:780
Hi all!
Here's a nifty probability question of a type you may not have seen before. If you have trouble solving it -- or can't see how you would even begin -- feel free to swing on by GMATT Mondays tonight, at the link provided in my sig file, where I'll walk you through intuitive approaches to fun, unusual problems like these. (We meet at 4PM Pacific, 7PM Eastern. This week's theme is probability, and there will be eight questions, four PS and four DS; hopefully I'll have time to go through all of them.)
--
I'm at a birthday party and I'm blindfolded. (Uh oh.) I'm currently standing in the First Room of the four rooms of the house, as shown.
Door <-> First Room <-> Second Room <-> Third Room <-> Fourth Room, with Cake!
I'm wandering from room to room with the following probabilities:
1:: If I'm in the first room, there's a 25% chance I walk out the door and a 75% chance I walk to the second room.
2:: If I'm in the second room, there's a 50% chance I walk to the first room and a 50% chance that I walk to the third room.
3:: If I'm in the third room, there's a 75% chance I walk to the second room and a 25% chance I walk to the fourth room (with cake!)
If I make it to the room with cake, I get to remove the blindfold and pig out. If I walk out the door blindfolded, however, the door is locked behind me and I'm banished from the party, without cake.
What are the odds that I get to pig out on cake?
A:: 3/32 B:: 3/16 C:: 1/3 D:: 3/8 E:: 1/2
Here's a nifty probability question of a type you may not have seen before. If you have trouble solving it -- or can't see how you would even begin -- feel free to swing on by GMATT Mondays tonight, at the link provided in my sig file, where I'll walk you through intuitive approaches to fun, unusual problems like these. (We meet at 4PM Pacific, 7PM Eastern. This week's theme is probability, and there will be eight questions, four PS and four DS; hopefully I'll have time to go through all of them.)
--
I'm at a birthday party and I'm blindfolded. (Uh oh.) I'm currently standing in the First Room of the four rooms of the house, as shown.
Door <-> First Room <-> Second Room <-> Third Room <-> Fourth Room, with Cake!
I'm wandering from room to room with the following probabilities:
1:: If I'm in the first room, there's a 25% chance I walk out the door and a 75% chance I walk to the second room.
2:: If I'm in the second room, there's a 50% chance I walk to the first room and a 50% chance that I walk to the third room.
3:: If I'm in the third room, there's a 75% chance I walk to the second room and a 25% chance I walk to the fourth room (with cake!)
If I make it to the room with cake, I get to remove the blindfold and pig out. If I walk out the door blindfolded, however, the door is locked behind me and I'm banished from the party, without cake.
What are the odds that I get to pig out on cake?
A:: 3/32 B:: 3/16 C:: 1/3 D:: 3/8 E:: 1/2
