Solution:

7x + 8x + 6x = 4200
x = 200
Now,
Pulkit = 7x = 7*200 = Rs. 1400
Rajesh = 8x = 8*200 = Rs. 1600
Tanmay = 6x = 6*200 = Rs. 1200

If we add Rs. 200 to each, the new amount will be
Pulkit = 1400 + 200 = 1600
Rajesh = 1600 + 200 = 1800
Tanmay = 1200 + 200 = 1400

Thus the new ratio will be 1600:1800:1400
Or 8:9:7

Solution:

Let the price of Chair be Rs. X
Let the price of Table be Rs. Y

Now as per the question
5x + 3y = 3110
-x + y = 210

Thus
4x + 4y = 3320
2x + 2y + 1660

Thus the required cost is Rs. 1660.

Solution:

Total amount after three years = 25500 + 8440.50 = Rs. 33940.50
Thus
[(100 + r) / 100] ^3 = 33940.50 / 25500 = 1.331

Thus r = 10%
So the simple interest will be
[25500*3*10) / 100]
= Rs. 7650

Solution:

4 + 44 + 444 + ....

= 4 [1 + 11 + 111 + ....]

= (4/9) [9 + 99 + 999 + ....]

= (4/9) [(10 - 1) + (10^2 - 1) + (10^3 - 1) + ... + (10^n - 1) ]

= (4/9) [(10 + 10^2 + 10^3 + ... + 10^n) - ( 1 + 1 + 1 + ... n times ) ]

= (4/9) {10 [(10^n - 1 ) / ( 10 - 1 ) ] - n(1) }

= (4/9) [(10/9) (10^n - 1) - n ]
= (4/81) [10^(n+1)-9n-10]

Thus option C is correct.

Solution:

Let us assume that he bought 100 Kg of antique stones for Rs. 100.

Then he sold the same stones for Rs. 90 while making a profit of 15%.

Thus CP of the sold stones = 90/1.15 = Rs. 78.26

Thus it means that the merchant sold 78.26 Kg in place of 100 Kg

Or we can frame the sentence as he is weighing 78.26 Kg for 100 Kg.

Solution:

My father's house is locate in the North West side of the food joint.

Solution:

This is a bit difficult series to crack and often puts the interviewee under pressure.

0 is the base one and something you need not focus on as it will be zero no matter what you do.
0.577 is the root of (1/3)
1 is the root of 1
1.732 is the root of 3

If you see the pattern, you will find that at every step the root digit is getting multiplied by 3.

Thus the next digit must be the root of 3*3 = 9
Root of 9 = 3 which is the next number in the sequence.

Solution:

Vikram's age = 73
His son's age = 37

Let the age of Vikram be V and age of his son be S
Now according to the question
V = 10a + b
S = a + 10b
V - 1 = 2 (S-1)
V = 2S - 2 + 1
V = 2S - 1

Thus
10a + b = 2a + 20b - 1
8a = 19b - 1

Which means
A = 7 and b = 3

Thus the age of Vikram = 73 and the age of his son = 37.

Solution:

It will take 68 minutes to complete one round of the larger garden.

Let the width of the smaller garden (rectangle) be 4 units
Then the length of the smaller garden will be 6 as it is fifty percent more
The perimeter of the garden = 2(6 + 4) = 20 units

20 units are covered in 20 minutes (as per the question)
Which means that it takes 1 minute to cover 1 unit.

In the large garden as per the question,
Width = 16 units and length = 18 units
Thus the perimeter = 2(16 + 18) = 68 units.

According to what we analyzed above, it will take the person 68 minutes to complete one round of the big garden.

Solution:

This is a bit tricky question that almost every time leaves the interviewee baffled.

Now take into consideration that the first friend can have his birthday in any of the months (there are 12 months all together).

All you have to find out is the probability that the second one will have his birthday in the same month which is a piece of cake.

The probability = 1/12.