Who is the author of ‘Harry Potter and the Prisoner of

58      83      133      ?       308       433

81, 41, 42, 64.5, ?, 330

80        81.5        83.5         ?         89           92.5

124, 107, 91, ? , 62, 49

What will come in place of the question mark (?) in the following series?

18, 26, 37, 51, ?, 88

114, 156, ?,  238, 274, 304

152        142       122      ?      52       2

What will come in place of the question mark (?) in the following number series?

180, 184, 168, 204, ?, 240

What will come in place of (?) question mark in the given number series.

11, 6, 7, 12, 26, ?

8 12 30 105 ? 2598.75