Select the related word/letters/number from the given

If 52 @ 15 = 15' and 38 @ 26 = 25', then 45 @ 31 = ?'. What will come in place of question mark?

How is V related to R?

Statements: N > U < I ≤ R < D < A; K ≥ O = G > X = E > A

Conclusions:

I. R < E

II. K > D

III. U ≥ X

Select the option in which the numbers are NOT related in the same way as are the numbers of the following set.

(21, 15, 72)

If 38 × 34 = 31, 34 × 58 = 25 and 56 × 67 = 43, then 28 × 32 = ?

If 87 # 95 = 101 and 48 # 84 = 64, then 68 # 87 = ? 

‘EXPLAIN’ is related to ‘YCGJLNV’ in the same way as ‘REQUEST’ is related to ‘___’.

Select the combination of letter that when sequentially placed in the blanks of the given series will complete the series.