A company allowed 9% commission on the total sales made

What value should come in the place of (?) in the following number series?

15, 21, ?, 41.16, 57.624

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

15, 26, 39, 56, ?, 98

51      52       48      57       ?       66       30

165        155      135      ?      65       15

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

86, 127, ?,  209, 250, 291

15.5, 62, 186, ?, 2232,  8928

52      83      114      ?      176       207

Complete the series choosing the missing number.

110, 99, 86, ___, 54, 35.

16, 20, 11, 27, ?, 38