26) Find the value of √ (13√(13√(13√(13√(13√(13√(13))))))).

√13

169

(13)^{(127/128)}

2197

Answer: C

Explanation:
When the process is not up to infinite, use this formula:
N ^{((2^t)-1 / 2^t)}, where the N is the digit, and t is the number of times the digit is repeated.
i.e., the number is 13, so we have: 13 ^{((2^7)-1 / 2^7)} =13^{(127/128)}
Hence, the required value is 13^{(127/128)}

27) Find the value of √ (248+ (√52+ (√144))).

4

8

12√2

16

Answer: D

Explanation:
When the numbers are different, then we have to move from right to left direction.
i.e., √144=12, √ (52+12) => √64 = 8
√ (248+8) = √256 = 16
Hence, the required value is 16.

Explanation:
This type of questions can be solved by a short trick that is the last term numerator, and the first term denominator will be the answer.
i.e., 1+1/2 = 3/2, 1+1/3 = 4/3, 1+1/4 = 5/4, and so on.
(3/2)*(4/3)*(5/4) .... ((x+1)/x) = (½) (x+1)
The first term numerator cancelled by its next term denominator till the end.
In the end, we get (x+1)/2.

30) (1-1/2)(1-1/3)(1-1/4) ....... (1-1/x) = ?

x

x-1

1/ (x-1)

1/x

Answer: D

Explanation:
This type of question can solve by a sort trick that is the first term numerator, and the last term denominator will be the answer.
i.e., 1-1/2 = 1/2, 1-1/3 = 2/3, 1-1/4 = 3/4 and so on
(1/2)*(2/3)*(3/4) .... ((x-1)/x) = (1) (1/x)
The first term denominator cancelled by its next term numerator till the end.
In the end, we get 1/x.