Which method used to preserves food by slowing down the

What will come in the place of questions (?) mark in the following questions.

160, 223, 271, 306, 330, ?

In each of the following number series, one term is missing. Find the missing term.

2, 6, 18, 54, 162, ?

2, 2, 6, 30, ?, 1890

10, 15, 25, 35, ?, 65

114, 156, ?,  238, 274, 304

144, 288, 96, 384, 76.8, ? 

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

40, 25, 30, 50, 105, ?

124, 107, 91, ? , 62, 49

18,  37,  60, ?,  120,  157

?, 6, 6, 9, 18, 45