GATE Questions

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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.

The given number series follows a pattern that,

9

9 x 0.5 + 0.5 = 5

5 x 1 + 1 = 6

6 x 2 + 2 = 14

14 x 4 + 4 = 60 (not equals to 56)

60 x 8 + 8 = 488.

Hence, the odd one in the given number series is 56.

'Autonomy' means personal independence. Hence, the word 'dependence' is farthest in meaning to the given word 'Autonomy'.

206 Bones in the Human Body.

The given number sequence is 101, 98, 93, 86, 75, ?

101

101 - 3 = 98

98 - 5 = 93

93 - 7 = 86

86 - 11 = 75

75 - 13 = 62

Here the series follows a pattern that consecutive subtraction of prime numbers.

Hence, the next number in the sequence is 62.

Here the given number series  3, 10.5, 36.75, 128.625, ? follows a pattern that

3

3 x 3.5 = 10.5

10.5 x 3.5 = 36.75

36.75 x 3.5 = 128.625

128.625 x 3.5 = 450.187

Hence the next number in the given number series is 450.187.

Given equation can be written as

$$\begin{gathered} 215 x 103 + ? = 24 \\ => 14 + ? = 24 \\ => ? = 24 - 14 \\ => ? = 10 \end{gathered}$$