Which method is considered the best for milking

Find the missing number in the given number series.

1, 2, 6, 24, 120, ?

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

4, 8, 24, ?, 480, 2880

4.8, 14, 62, ?, 1516, 7578 

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

75, ?, 107, 148, 229, 390

5, 18, 39, ?, 105, 150

36, 72, 47, 63, ?, 58

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

4, 11, 32, 95, 284, 851, ?

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

11           20           ?              64           112         192