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8/31/2008 1:18 PM |
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We are providing solutions to the Crazy Questions at Google Job Interview post By Thiomir
- How many golf balls can fit in a school bus?
Solution:
The point of the question isn't to see how golf balls you think are in
the bus, but to see what your deduction skills are like. Do you just
make a random guess or try to cop out by saying a lot, or do you
actually try to come up with a legitimate answer by going through a
logical series of steps.
- 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?
Solution:You
simply jump out. As you are scaled down, the ratio of muscle mass to
total mass remains the same. Potential energy is given by E = mgh. So,
if E/m is unchanged (where E is the energy expended in expanding your
leg muscles, and m is your mass), then h is unchanged. Mini-me jumps as
high as me. This is the reason why grass-hoppers can jump about as high
as people.
- How much should you charge to wash all the windows in Seattle?
Solution:As
crazy as it might sound, questions like these demonstrate your ability
to think through a complex problem with little or no information. They
expect you to take an educated guess. Most of the time you can ask them
questions like - how many buildings are there in Seattle.
- How would you find out if a machine’s stack grows up or down in memory?
Solution:Instantiate
a local variable. Call another function with a local. Look at the
address of that function and then compare. If the function's local is
higher, the stack grows away from address location 0; if the function's
local is lower, the stack grows towards address location 0.
- Explain a database in three sentences to your eight-year-old nephew.
Solution:A
database is like a file cabinet. The files, or data, is stored in it
and can be arranged in categories. But unlike an actual file cabinet,
you can do a lot more cool stuff with a database like being able to
make it accessible through the internet.
- How many times a day does a clock’s hands overlap?
Solution:The
Hour hand and Minute hand would be meeting exactly 11 times in 12 hours
(Hour hand would have taken 1 clockwise round and Minute hand would
have taken 12 clockwise rounds, so 12 - 1 = 11 rounds).
result:
First time hour and minute hands overlap will be 12 Hours / 11 =
01:05:27.27. So at this time only hour and minute hands would be
overlapping and second hand will not be any near to them. Similarly for
2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th and 10th overlap of hour and
minute hand the Second hand wont be any nearby. So all 3 hands (hour,
minute and Second) overlap only 2 times i.e. (0:0:0 and 12:0:0).
Also we all know when we get our watches repaired, normally the repairman overlaps all the three hands to 12.
If we are considering that the second hand is not present, then the rest two overlaps 22 times in 24 hours.
There again is a catch, if we check the angles by which the hour hand and minute hand moves.
The
second hand moves 6 degree in a second. In that time the minute hand
will move 6/60 degrees. and the hour hand will move 6/(60*12) degrees.
now taking these things in the considerations. if we check the
positions of the hour and minute hand in terms of angle from the marker
12, for our first rendezvous time, i.e. 01:05:27.27 sec.
first thing
that comes to my mind is that, there is fraction in the seconds. So
that time can’t be measured. there will be no exact overlap. now lets
calculate the angles:
1 hour 5 mins and 27 seconds = 3600 + 5*60 + 27 = 3927 seconds.
angle of hour hand = 3927 * 6/(60*12) = 32.725 degree.
angle of minute hand = 3927 * 6/60 = 392.7 degree
subtracting 360 degree from it we get - 32.7 degree.
So at 01:05:27 both hands don’t overlap. Now for 01:05:28 :
Angles : hour hand - 32.73333
minute hand - 32.8
so obviously they dont meet at 01:05:28 either.
So they overlap at 12:00 and 24:00 only. So the answer is 2 only.
- You have to get from point A to point B. You don’t know if you can get there. What would you do?
Solution:Utilizing
a “learn as you go” approach and applying collected knowledge and data
along the way is the best way to proceed. Let’s break this down farther.
Determine
the amount of time you have to go from point A to point B. Spend the
initial 20% of that time making a 360° search with the largest
circumference possible with the in the time you have allowed.
During
that time, ask people, look for maps, clues, collect data, and
knowledge. At the end of the initial 360° search take an objective look
at all the information you have obtained and you calculate the risk of
failure you are willing to live with. Create a plan and a strategy
based on your assessment of where you believe point B to be. Then you
proceed on implementing your plan with predetermined intervals of
reassessment and strategy improvements.
This is the best chance you have reaching point B if you don’t know if you can get there.
- 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?
Solution:Let’s suppose there are
a
set of attributes of each shirt you are interested in: e.g. sleeve
length, color, buttons (no buttons, fully button, partially buttoned
from collar to chest level).
Let’s say the closet is a simple wall
closet with a single closet rod running the entire length of closet. On
the left you put all the short sleeve shirts, and on the right the long
sleeve shorts. You separate then long and short sleeve sides with a
specially marked coat hanger. Then you separate each group into no
buttonoed, partially buttoned, and fully button, using more specially
marked hangers. Then each sub group is separated into colored and
monochrome sub-sub-groups (specially marked hangers aren’t needed for
separators unless you are color blind) Then each colored group is
sorted left to right according to the color spectrum: ROYGBIV: red,
orange, yellow, green, blue, indigo, violet. Each monochrome ggroup is
sorted left to right: white on the left, black on the right, and shades
of grey in the middle, the darker greys on the right, the lighter on
the left.
- 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?
Solution:1. There is only one cheat husband
-
If it is so then 99 wives knew it before. So the cheated wife got the
idea from queen that her husband is cheating. So she will kill him.
Next morning every wife will know there is no cheat husbands anymore.
2. There are more than one cheat husbands
-
In this case, all of the wives already had the idea prior to queen's
information. Its just that the cheated wives knew the count which is
one less than what the non-cheated wives' knew - thats all. i.e. if
there were 2 cheat husbands then their wives knew the count is 1 and
others knew its 2. So the queen just repeated the info saying "at least
1". Same goes to 2,3,4...100 cheat husbands. So in this case no wife
kills her husband.
- 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?
Solution:From pure probability,we get the expected number of girls born to be 1/2 with that of boys being 1.So the ratio is 2:1
- 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)?
Solution:If the
chance to see the car is 10 percent per minute, the first minute you
have 10% chance, the second minute you have 10% of 90% = 9% (so total
19%), the third minute 10% of 81% (= 8,1%, total 27,1 %) ......
As the chance for 30 minutes is 95 percent, the chance for 1 minute is 9.5% and for 10 minute 63.1 %.
- 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!)
Solution:7.5
degrees (the hour hand is 1/4th of the way between 3 and 4, the angle
measure of that is 360/12 = 30 degrees between hours / 4 = 7.5 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?
Solution:1
and 2 cross, taking 2 minutes, 1 goes back carrying the flashlight
total=3 minutes. 5 and 10 cross, taking 10 minutes totaltime now= 13
minutes, 2 goes back,total time now = 15 minutes. 1 and 2 cross again,
taking 2 minutes making it 17 minutes.
- 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?
Solution:No.
- How many piano tuners are there in the entire world?
Solution:1) At first list out all the piano manufacturing companies in the world.
2) Then look into their purchase records and find out the piano purchasers information.
3)
i) If the purchase is made by an individual or a house hold then the
piano is played at best case by all the people of the house.
ii) Else if the piano is purchased for school then list out the students that opted the piano course in their music curriculum.
iii) If the piano is purchased by a Church then count the no of major or minor events of the church and count the piano users.
sum up all the numbers to get more or less accurate piano users count.
- 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?
Solution:choose 6 balls and weigh 3 against 3
- if they weigh the same, you have another weighing for the remaining 2 balls and you can find the heavier one
- if they don’t weigh the same, from the group of 3 which was heavier, choose any 2 balls and weigh them:
-
if they weigh the same, the remaining ball is the heavier one;
otherwise you just found the heavier one by weighing the 2 chosen balls.
- 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.)
Solution:The highest ranked pirate gets 98 gold coins
---Two pirates get 1 gold coin each
---The other 2 pirates get nothing.