If x - √3 y = 8 Find the slope in

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

1458, ?, 162, 54, 18, 6

Find the missing number in the given number series.

2, 5, 11, 23, 47, ?

257, 399, 566, ?, 983, 1237 

18      29      16      31      ?      33

38% of 18/225 of 31/19 of 15225 =?

13, 41, 69, ?, 125, 153 

3, 8, 18, 33, 53, ?

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

256, 128, 64, 32, 16, ?

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

175, 160, 140, 115, ?

Find the missing number in the given number series.

?, 6, 30, 210, 1890, 18900