##### Interview Logic Questions

Since I’ve been so nervous about getting this job, I decided to go on the search of google job interview questions. While, I’m pretty sure I won’t get asked any of them, I find them quite fun to try and figure out. So, I’m going to try and figure them out. (Note: Yes, some sites had answers so I cheated…) Feel free to provide your own interpretations or questions.

Obtained from: http://careers.cse.sc.edu/googleinterview

- How many golf balls can fit in a school bus? This is a Fermi question.

Hehe.. my years as a bus driver come into play! What size of bus is it? A 44 pax can hold almost double a 28 pax. Also, a bluebird has more space in front than a freightliner bus. Now, lets say you have a bus that is 10,000 balls longs, 1,000 balls high, and 1,000 balls wide, you would have a lot of balls. (10,000,000,000) Minus 1/10 for seats I would say a billion. Or… at least one. 🙂 - You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving in 60 seconds. What do you do?

Lets see. I’m 71 inches, which is about 180 cm. I’m guessing a nickel is about 5mm. Thus, I would be 1/360th of my original height. Now, I know blood cells are small, but I know there is no way one of those would be able to handle an oxygen molicule at that size. So, I would think I would die from suffication about that time. However, assuming there were no health complications, I would just sit under the blades, cover my ears, and watch. Blender blades are straight, and use the weight of the objects suspended in a liquid to move the objects into the blades. As the objects are chopped up, they filter to the top to let the heaver objects come meet their doom. However, since the blades are straight, it does not push air as one would expect. If I kept my density I would be in no danger of being ‘sucked’ into the blades. It would, however, be really really loud.(I looked it up, a red blood cell is 6-8 µm. An oxygen molicule is 60pm. 60 pm is .00006 µm. 1/360 of a red blood cell is still over 22 thousand times bigger than an oxygen molycule, so I was obviously way wrong. Goes to show how much I know about chemestry. (Sorry maruchan) Good thing I added a second option.)

- How much should you charge to wash all the windows in Seattle?

Man, I hate these ones. I’m (really) bad at estimating things likes how many buildings are in Seattle… All right, lets assume there are 500,000 buildings in Seattle. Lets assume there are an average of 20 windows per building. Since I’m the best window washer in seattle (why else would everyone want me?) my prices are high. Lets say $20/window if it’s on the ground floor, and $30 per window if it’s on the second floor or higher. Assuming that 20% of all buildings have more than one floor… (20% == 1/5 == 100,000 second floor buildings. 🙂 So, that equals $8,000,000 for first floor, and $3,000,000 for second floor or more. So, for $11 billion dollars I will be stuck washing windows for the rest of my life. - How would you find out if a machine’s stack grows up or down in memory?

int Var1 = rand(); int Var2 = rand(); cout << "The stack grows " << (&Var1 > &Var2) ? “Down” : “Up” << "." << endl; To explain. You initilize two variables. Then you look at their memory address. If the second variable is a larger memory address than the first, it means the stack grows up, and vice versa. - Explain a database in three sentences to your eight-year-old nephew.

It’s like your mom. She knows where everything in the house is and will tell you if you ask right. Except this mom is in the computer. 🙂 - How many times a day does a clock’s hands overlap?

11 times. Unless it’s a digital clock, then never. This, of course, assumes a day consists of a 12 hour period between like 8am to 8pm. - You have to get from point A to point B. You don’t know if you can get there. What would you do?

If you have to get somewhere, then you just have to do it. There are always uncertainties in life, but if you never try, you’ll never know. So, you start walking. Eventually you’ll make it to your destination, even if it wasn’t where you were originally planning to go. - Imagine you have a closet full of shirts. It’s very hard to find a shirt. So what can you do to organize your shirts for easy retrieval?

Leave them the way they are and ask the wife to get my shirt for me. (They said easy…) I would arrange them by type and color. Button up shirts to the right, polos in the middle, tee-shirts to the right. Then arrange those by color. That way, you know the general area a shirt will be in. If you always wear the same shirts, keep them in the dryer. 🙂 - Every man in a village of 100 married couples has cheated on his wife. Every wife in the village instantly knows when a man other than her husband has cheated, but does not know when her own husband has. The village has a law that does not allow for adultery. Any wife who can prove that her husband is unfaithful must kill him that very day. The women of the village would never disobey this law. One day, the queen of the village visits and announces that at least one husband has been unfaithful. What happens?

I don’t think anything will happen. If every man in the villiage cheated with a different women every day, the women would know someone was being cheated on every day. Even after 100 days, they would have no proof it was their husband since they would be getting at least 99 hits a day. (More if the men cheated more than once a day.) Then again, I think the wives would get suspicious and start to monitor their husbands behavior and catch them in the act, but that’s just me. - In a country in which people only want boys, every family continues to have children until they have a boy. if they have a girl, they have another child. if they have a boy, they stop. what is the proportion of boys to girls in the country?

It would be a 50/50 ratio. - If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes (assuming constant default probability)?

Well, I would assume it would be 1/3 of what it would be at 30 minutes, or about 32%. I know this is wrong though. I’ll have to dive into my probability and statitic books when I get home to remind myself how to do this. - If you look at a clock and the time is 3:15, what is the angle between the hour and the minute hands? (The answer to this is not zero!)

Well, lets take 12:00 as 0deg. So, at 3:00, the minute hand goes 1080 deg, however, the hour hand move 45 degrees as well. So, 1,035 degrees. - Four people need to cross a rickety rope bridge to get back to their camp at night. Unfortunately, they only have one flashlight and it only has enough light left for seventeen minutes. The bridge is too dangerous to cross without a flashlight, and it’s only strong enough to support two people at any given time. Each of the campers walks at a different speed. One can cross the bridge in 1 minute, another in 2 minutes, the third in 5 minutes, and the slow poke takes 10 minutes to cross. How do the campers make it across in 17 minutes?
The 1min man has the 10min man hop on his back and runs across. 1min.

The 1min man goes back across the bridge. 2min.

The 1min man carries the 5min man on his back. 3min.

The 1min man goes back across the brige. 4min

The 1min man tells the 2min man to get his ass across since he’s sick of carrying people. 6minThe other two options: The 1-2 min guys go across the bridge. Walk in dark to camp. Grab tent. Walk back to bridge. Set up camp on that side. Or just wait until dawn. (Or, I guess…survival of the fittest. Sorry Mr. 10min.)

- You are at a party with a friend and 10 people are present including you and the friend. your friend makes you a wager that for every person you find that has the same birthday as you, you get $1; for every person he finds that does not have the same birthday as you, he gets $2. would you accept the wager?

I remember dealing with the birthday problem back in prob and stats. I would not take this bet unless all the money came from him. If there were 23 people at the party, there would be a 50% chance that someone would have the same birthday as you. At 59 people, it’s almost a guarentee someone will. Either way, if he gets 2 for any that doesn’t, and you get 1 for any that does, even if half of them had your birthday he would end up with all the money. - How many piano tuners are there in the entire world?

Another Fermi. Meh. So, 6 bil people in the world. Lets say 1 in 100 have a piano. And lets say 1 in 100 of those actually tune their piano per year. And .. 2. There are two. And one just sued the other for having a monopoly. - You have eight balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more. How can you find the ball that is heavier by using a balance and only two weighings?

Easy. Weigh 3/3. If they’re equal, weight the other two. If not equal, weight one ball each. - You have five pirates, ranked from 5 to 1 in descending order. The top pirate has the right to propose how 100 gold coins should be divided among them. But the others get to vote on his plan, and if fewer than half agree with him, he gets killed. How should he allocate the gold in order to maximize his share but live to enjoy it? (Hint: One pirate ends up with 98 percent of the gold.)

You’re supposed to look at this in reverse:

1 pirate – Gets 100% of the gold.

2 pirates – Pirate 4 gets 100% of the gold with half the vote. Pirate 5 gets nothing.

3 pirates – Pirate 3 gives Pirate 5 1 gold piece. Pirate 5 will accept knowing if he doesn’t he’ll get nothing.

4 pirates – Pirate 4 will give pirate 5 1 gold piece, again, that pirate will accept knowing he won’t get better.

5 pirates – Will give pirate 4 and 5 1 gold piece. They’ll both accept knowing they won’t get better if they decline.So, pirate five gets 98% of the gold, and the other two gold pieces goes to pirate 4 and 5.

Afterwards, when pirate 1 thought he got away with it, he was stabbed in the back by pirate 3. This caused pirate 2, who was actually pirates 1 homosexual lover to kill pirate 3 in a lovestricken rage. Pirate 4, who always was a little homophobic, kills pirate 2 while he is still grief stricken and steals the money. Pirate 5 spent his 1 gold piece on a prostitute who gave him a deadly STD. She wasn’t very good anyway. Pirate 4 spends his time at the county jail where he was caught with 99 gold pieces and a bloody dagger. He spends his time trying to convince people that it really wasn’t a hate crime and is eventually shanked in the showers by his cellmates ‘bitch.’ The 1gp was used to cure the prostitute of the STD and turn her life around where she became a leading sexual health doctor. The 99gp were aquired by the local government where they spent it on “Stop the Violence” campaigns.

*Related*

Filed under: Uncategorized - @ October 21, 2007 12:57 pm

Tags: logic questions