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Q37·CSAT · Prelims 2026

Quantitative — Recurrence Series Patterns

ReasoningSeries — Number PatternSeries & PatternEasy

Question

In a sequence of numbers, each number other than the first two is the sum of the two immediately preceding numbers from it. If the first two numbers in the sequence are 4 and 7, then the sixth number is [cite: 4241, 4242]

Options

a

29

b

37

c

43

Answer
d

47

Explanation

The series follows an additive recurrence rule where T_n = T₍n-1₎ + T₍n-2₎ for all positions n \ge 3 .

Let us calculate the values for each position step-by-step starting from the given initial terms :

T_1 = 4
T_2 = 7
T_3 = T_2 + T_1 = 7 + 4 = 11
T_4 = T_3 + T_2 = 11 + 7 = 18
T_5 = T_4 + T_3 = 18 + 11 = 29
T_6 = T_5 + T_4 = 29 + 18 = 43

Thus, the sixth number in this sequence is exactly 43.

Finding terms in a recursive sequence involves sequentially adding the two preceding terms in order without skipping steps.

Answer: (c).

Question details

Year

2026

Paper

CSAT

Question

Q37

Section

Logical Reasoning

Sub-topic

Series — Number Pattern

Type

Series & Pattern

Difficulty

Easy

Source hint

Fibonacci-style series — additive recurrence relations

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