St' paul's school Interview Questions, Process, and Tips

A perfect square is a square number of a digit. eg 64 is a perfect number, a square of 8
Now digits AB9 is a square number of a number.
AB9 Can also be written as A multiply by B multiply by 9
Get the Square root of AB9
Assumption, A=1, B=1
1*1=1=A, 1*1=1=B Therefore,
Square root of A = A, B = B and 9=3
Therefore
An odd number is a number indivisible by 2.
for example 1,3,5,7…….
Therefore Squares A*B*9= AB9
Where a=1, b=1, 3 as digits.
Conclusion
A=1 is an odd number

27

20×20+22×22+24×24= 1460
Numbers is less then 30 because 30 square is 900 we have to take three consecutive number if we take numbers greater than 30 the sum of that numbers wil be greater than 1460.

Relative velocity of trains = 49kmph -25 kmph = 24kmph
=6.67m/s
Time taken to cross the first train = 10 sec
Length of the second train = Relative Velocity * Time taken
to cross the first Train = 6.67 *10 = 66.7 metres

The number is greater than the number obtained in reversing the digits and the ten’s digit is greater than the unit’s digit
Let ten’s and unit’s digit be 2x and x respectively
Then, (10×2x+x)−(10x+2x)=36
9x=36
x=4
Required difference=(2x+x)−(2x−x)=2x=8

500

q

3

Assume his salary was Rs. X
He earns 5% raise. So his salary is (105*X)/100
A year later he receives 2.5% cut.
So his salary is ((105*X)/100)*(97.5/100)
which is Rs. 22702.68
So Ans is Rs.22176

Ans 635.5
4000
1 year 5 % 200 rs int
Total 4200
2 year 5 % 210 ra int
Total 4410
4410-2210 = 2200
1 year 5% 110
Total 2310
2 year 5 % 115.5 rs int
Total 2425.5
Total interest paid
200 +210+ 110+115.5. = 635.5

3630

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