Interview Question

Q: How many times a day a clock’s hands overlap?

In any circular motion, if the ratio between 2 fellow is n:1 then for each lap of the slower fellow, faster fellow overlaps him n times, except for the last lap of the slower fellow, where the number of crossings are n-1. (The race just finishes before the n th cross.
slower fellow : hour hand (short)
faster fellow : minuite hand (long)
n = 12
Total laps for hour hand = 2
total overlaps = 12+11 = 23.


Q: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!)

The time is 3:15, i.e. 25% of the time between 3 and 4 has passed. The hour-hand should, by simple mechanical logic, have moved 25% of its total distance between 3 and 4.
The total angle the hand covers is 360%, so the angle covered between 3 and 4 should be 360/12 = 30 degrees.
The minute hand is smack on 3, and the hour hand is a quarter of 30 degrees further on. The angle made between them is thus 30*1/4 = 7.5 degrees


Q: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)?

If you have a solution why do not you share it with us



Q: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?


Assuming both having a boy or a girl are equal in probability then the ratio is 1.



Q:What method would you use to look up a name in a dictionary?

Do you remember that game 20 questions? You have to ask 20 questions to guess a word. The way to cheat is to narrow it down by half every time. The English dictionary has about 500,000 words, meaning you would still have queries to spare.
Yes, it would be boring, but it would go something like this:
Does your word come before the word “marry”? Yes
Does your word come before the word “gerrymander”? You get the point.
Assuming you already know you have to sort, you can binary search at O(log_2 N). For this, say, a trillion, is less than 50.
But its application doesn’t stop there, as it -as well as its cousin ternary search- can help you solve numerical equations (this is actually called bisection). For example, you want to find the cube root of N (N^(1/3)), but don’t have any sort of library ready. Easy solution? Binary search! You know x=y^3, so “guess” a value for x, and go from there!


Q: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 fine the ball that is heavier by using a balance and only two weighings?


Q:How do you cut a rectangular cake into two equal pieces when someone has already taken a rectangular piece from it? The removed piece an be any size or at any place in the cake. You are only allowed one straight cut

Q:A software engineer has the capability of thinking 100 lines of code in five minutes and can type 100 lines of code in 10 minutes. He takes a break for five minutes after every ten minutes. How many lines of codes will he complete typing after an hour?

250 lines of code

Q:If 75 men can complete a piece of work in 20 days. How much longer will it take to complete the work by 50 men?

30 days.
Explanation:
With the 75 men case:
One day work = 1 / 20
One man’s one day work = 1 / ( 20 * 75)
Now with the 50 men case:
No. Of workers = 50
One day work = 50 * 1 / ( 20 * 75)

The total number of days required to complete the work = (75 * 20) / 50 = 30 days.


Q:An empty swimming pool can be filled to capacity through an inlet pipe in 3 hours, and it can be completely drained by a drainpipe in 6 hours. If both pipes are fully open at the same time, in how many hours will the empty pool be filled to capacity?