Aptitude Interview Questions And Answers 
1. A three digit number consists of 9,5 and one more number . When these digits are reversed and then subtracted from the original number the answer yielded will be consisting of the same digits arranged yet in a different order. What is the other digit?
Sol. Let the digit unknown be n.
The given number is then 900+50+n=950+n.
When reversed the new number is 100n+50+9=59+100n.
Subtracting these two numbers we get 89199n.
The digit can be arranged in 3 ways or 6 ways.
We have already investigated 2 of these ways.
We can now try one of the remaining 4 ways. One of these is n 95
100n+90+5=89199n
or 199n =796
so, n=4
the unknown digit is 4.

2.
A farmer built a fence around his 17 cows,in a square shaped region.He used 27 fence poles on each side of the square. How many poles did he need altogether???
Ans.104 poles
Sol. Here 25 poles Must be there on each side .And around four corners 4 poles will be
present. 4*25+4=100+4=104 poles.

3.
On the first test of the semester, kiran scored a 60. On the last test of the semester, kiran scored
75%
By what percent did kiran's score improve?
Sol. In first test kiran got 60
In last test he got 75.
% increase in test ( 60(x+100))/100=75
0.6X+60=75
0.6X=15
X=15/0.6=25%

4.
A group consists of equal number of men and women. Of them 10% of men and 45% of women are unemployed. If a person is randomly selected from the group. Find the probability for the selected person to be an employee.
Ans:29/40
Sol: Assume men=100,women=100 then employed men & women r (10010)+(10045)=145
So probability for the selected person to be an employee=145/200=29/40 
5.
Randy's chain of used car dealership sold 16,400 cars in 1998. If the chain sold 15,744 cars in1999,by what percent did the number of cars sold decrease?
Ans: 4%
Sol. Let percentage of decrease is x , then
16400(100x)/100=15744
1640015744=164x
x=656/164=4% 