Elon Musk bought _____ % stake in Social Networking App

Find the missing number in the given number series.

 58, 86, 142, ?, 478, 926

7, 6, 10, 27, 104, ? 

Find the missing number (?) in the given number series.

2, 6, 18, 54, ?, 486

A series given below follows a certain pattern,

1800, 469, (?), 855, 980, 953

If (?) = B – 2, then find the nearest cube root of B.

142, 148, 160, 178, ?, 232

15.975 ×27.825 + (76.01)² + 12.98×18.426 = ?+ (79.09)²

43, 56, 82, ?, 173, 238

4, 9, 24, 69, ?, 609

2, 2, 6, 30, ?, 1890

Find the missing number in the given number series.

3, 7, 18, 38, 69, ?