Campus Interview Questions

These questions are collected and compiled solely by me. some of them are even created by me ;).
If you are bored doing RSAgarwals and Shakunthala Devi's(SD), then try solving these and it will be a good respite for you. If you haven't finished RS or SD, forget about this, go back and try solving them. Well, the following are the questions and I shall post the answers in a different blog, so that you can analyse your answers when ever you want! :)

1. Tell me the most efficient way of finding a square root of a perfect number.
2. Tell me the most efficient way of finding sum of all the factors of a number.
   
3. Most efficient way of multiplying vth 7 without using *.
   
4. Tell me the series where sum of any n numbers in the series is not equal to another number in the series. Eg: 4, 6, 10 can't be the required series; 2,3,4,9 can't be the required series.
5. If Ravi is as old as Kavi was when Ravi was one third older as that of Kavi is, then what are the ages now? (source: 7th class text book.)
   
6. If we have 80 coins out of which one weighs lesser than the rest, what is the minimum no of weighings required to find the counterfeit using normal balance?(SD, twisted a bit!)
7. Supposing we have 10 heaps of 10g coins out of which one heap has 9g coins. Tell me the way to find out the counter-feit coins heap weighing only once.(Assume you have electronic balance.) [Last year Oracle question.]
   
8. If + indicates *, - indicates /, * indicates - and / indicates +, what is the value of (2+3)*(4-2)/((2*1)+(4/3))? (My Creation!)
   
9. Tell me the easiest way of finding whether a double value is integer or not? Hint: Use Elementary Mathematics! (My creation!)
10. My favourite from SD: If a pendulum clock rings for 6 secs when the time is 6pm. How long does it ring when the time is 10pm?
    

Happy Solving ;). Answers in another blog!