Fill in the blank space for the given series with the correct alternative.
$0.5, 0.55, 0.65, 0.8, (...)$

Choose the correct alternative for the missing term:
$2 A 11, 4 D 13, 12 G 17, ?$

The positions of the first and the second digits in the number $7986032451$ are interchanged. Similarly,the positions of the third and fourth digits are interchanged,and so on. Which of the following will be the fifth digit from the right end after the rearrangement?

Find the missing letters for the given series from the given alternatives:
$acc....bc....a....ccbbcc.....$

Choose the correct alternative to fill in the blanks for the series: $cab....a....c....be....be....b....ab$

Two terms have been put within brackets. Mark your answer as:
$4, 7, (9), 10, 13, 15, (16), 19$