How many 10 digit numbers can be formed using the digits

4, 4, 5, ? , 248, 1248

25     25     37.5     ?     328.125     1804.6875

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

35, 38, 46, ?, 85, 120

21         24          22         25       23         ? 

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

100, 729, 64, 343, 36, ?

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

15, 90, 450, ?, 5400, 10800 

257, 399, 566, ?, 983, 1237 

23       44      64      83       ?        118

120, 115, 120, 135, 160, ?

5, 23, 18, 36, 31, ?