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Series Completion
1.120, 99, 80, 63, 48, ?

Explanation:

Solution:
The pattern is - 21, - 19, - 17, - 15,.....
So, missing term = 48 - 13 = 35.

2.589654237, 89654237, 8965423, 965423, ?

Explanation:

Solution:
The digits are removed one by one from the beginning and the end in order alternately
so as to obtain the subsequent terms of the series.

3.3, 10, 101, ?

Explanation:

Solution:
Each term in the series is obtained by adding 1 to the square of the preceding term.
So, missing term = (101)2 + 1 = 10202.

4.125, 80, 45, 20, ?

Explanation:

Solution:
The pattern is - 45, - 35, - 25, .....
So, missing term = 20 - 15 = 5.

5.1, 1, 4, 8, 9, 27, 16, ?

Explanation:

Solution:
The series consists of squares and cubes of consecutive natural numbers i.e. 12, 13, 22, 23, 32, 33, 42, .....
So, missing term = 43 = 64.

6.1, 2, 3, 6, 9, 18, ?, 54

Explanation:

Solution:
The pattern is x 2, x 3/2, x 2, x 3/2, x 2,.....
So, missing term = 18 x 3/2 = 27.

7.6, 13, 25, 51, 101, ?

Explanation:

Solution:
The pattern is x 2 + 1, x 2 - 1, x 2 + 1, x 2 - 1,.....
So, missing term = 101 x 2 + 1 = 203.

8.1, 3, 4, 8, 15, 27, ?

Explanation:

Solution:
The sum of any three consecutive terms of the series gives the next term.
So, missing number = 8 + 15 + 27 = 50.

9.3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ?

Explanation:

Solution:
The given sequence is a combination of two series :
I. 3, 7, 13, 21, 31, ? and II. 4, 7, 13, 22, 34
The pattern in I is + 4, + 6, + 8, + 10,.....
The pattern in II is + 3, + 6, + 9, + 12,.....
So, missing term = 31 + 12 = 43.

10.198, 194, 185, 169, ?