Which number replace the question mark?

Find the missing number in the following images.

Find the missing number from the given figure?

In the following question, select the number which can be placed at the sign of question mark ( ?) from the given alternatives .

Select the letter-pair that can replace the question mark (?) in. the following series
BA, DC, FE, HG, ? , LK

Find the missing number from the given responses.

19 ( 36 ) 13 and 37 ( 81 ) 28, then what is the value of A in 43 ( A ) 38.