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RRB NTPC Prelims Model Paper 1 with solutions

Question : 5 of 100

Marks: +1, -0

Find the missing term : 7, 9, 13, 21, ___?__ .

Solution:

Concept:

The pattern is formed by adding successive powers of

2

to each term.

Explanation:

Find the differences between consecutive terms.

9 - 7 = 2

13 - 9 = 4

21 - 13 = 8

The differences are

2, 4, 8

, which double each time.

Next difference

= 8 \times 2 = 16

So, missing term

= 21 + 16 = 37

Answer:

37

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