If 16 : X :: X: 196, find the positive value of x?

Which of the following numbers will replace the question mark (?) in the given series?

67, 78, 71, 82, 75, 86, ?

Select the number that will replace the question mark (?) in the given number series.
 146, 90, 56, 34, 22, ?

Find the value of p, when p= ( 5÷ 6 ) of 54 - 40 + 10 - 41 - 22

Which of the following numbers will replace the question mark (?) in the given series?

5103, 1701, 567, ?, 63, 21

Select the number from among the given options that can replace the question mark (?) in the following series.
728, 717, 695, 662, 618, ?

Direction: What value will come in place of the question mark (?) in the following question?

1, ?, 3, 15, 105, 945

Select the number from among the given options that can replace the question mark (?) in the following series.
 34, 102, 612, 5508, ?