What number should replace the question mark?

125, 138, 164, ?, 255

Here the given series 7, 11, 19, 35, ?

follows a pattern that (x 2 - 3) i.e,

7

7 x 2 - 3 = 11

11 x 2 - 3 = 19

19 x 2 - 3 = 35

35 x 2 - 3 = 67

67 x 2 - 3 = 131

Hence the next number in the given number series is 67.

The Given number series 3, 6.5, 14, 29, 64, 136 follows a pattern that

3

3 x 2 + 0.5 = 6.5

6.5 x 2 + 1 = 14

14 x 2 + 2 = 30 ≠29

30 x 2 + 4 = 64

64 x 2 + 8 = 136

Thus the wrong number in the series is 29

The given number series follows a pattern that

196, 169, 144, 121, 100, 81, ?

    -27  -25   -23   -21  -19  -17

=> 81 - 17 = 64

Therefore, the series is 196, 169, 144, 121, 100, 81, 64.

Here the given series 1, 6,  ?, 15, 45, 66, 91 follows a

Pattern in the series is, +5, +9, +13,...,.. +21, +25

So +4 is getting increased at every term addition.

Missing Number in the series will be 15+(9+4) = 15 + 13 = 28.

Arithmetic Series ::

An Arithmetic Series is a series of numbers in which each term increases by a constant amount.

How to find the sum of the Arithmetic Sequence or Series for the given Series ::

When the series contains a large amount of numbers, its impractical to add manually. You can quickly find the sum of any arithmetic sequence by multiplying the average of the first and last term by the number of terms in the sequence.

That is given by Sn = n(a1 + an)2 Where n = number of terms, a1 = first term, an = last term

Here Last term is given by an = a1 + n-1d where d = common difference

Now given Arithmetic Series is 

2, 5, 8, 11,...

Here a1 = 2,  d = 3, n = 36 

Now, $$\begin{gathered} an= a1 + n - 1d \\ a36= 2 + 36 - 13 = 105 + 2 = 107 \end{gathered}$$

Now, Sum to 36 terms is given by

S36 = 36(2 + 107)2 = 36 x 1092 = 39242 = 1962

Therefore, Sum to 36 terms of the series 2, 5, 8, 11,... is 1962.

Given nuber series is 15, 30, ? , 40, 8, 48 

Here the number series follows a pattern that

15

15 x 2 = 30

30 ÷ 3 = 10

10 x 4 = 40

40 ÷ 5 = 8

8 x 6 = 48

Hence, the missing number in the series is 10.

Given Number series is :

3   4   14   48   576   27648

It follows a pattern that,

3

4

4 x 3 = 12   but not 14

12 x 4 = 48

48 x 12 = 576

576 x 48 = 27648

Hence, the odd one in the given Number Series is 14.

Here the given number series is 3, 14, 36, 67, 113, 168

It follows a pattern that

3

3 + 1 x 11 = 3 + 11 = 14

14 + 2 x 11 = 14 + 22 = 36

36 + 3 x 11 = 36 + 33 = 69

69 + 4 x 11 = 69 + 44 = 113

113 + 5 x 11 = 113 + 55 = 168

Hence, the wrong number is 67.