General Intelligence
Number Series
Number Series
Q. #6563 (CAT-I)
Find the missing term in the following alternating sequence:
3, 8, 5, 27, 8, 64, 12, 125, 17, ?
A.
216
B.
361
C.
624
D.
442
View Answer & Explanation
• The sequence alternates between two distinct patterns:
First series (odd positions): 3, 5, 8, 12, 17
3 + 2 = 5
5 + 3 = 8
8 + 4 = 12
12 + 5 = 17
Second series (even positions): 8, 27, 64, 125, ?
2³ = 8
3³ = 27
4³ = 64
5³ = 125
6³ = 216
• Therefore, the missing term is 216.
General Intelligence
Number Series
Number Series
Q. #6562 (CAT-I)
Find the wrong number in the given series:
3, 6, 7, 9, 11, 14, 15, 18
View Answer & Explanation
• The series is formed by two alternating sequences:
Odd positions: 3, 7, 11, 15
3 + 4 = 7
7 + 4 = 11
11 + 4 = 15 (Correct)
Even positions: 6, 9, 14, 18
6 + 3 = 9
9 + 4 = 13
13 + 5 = 18
• Instead of 14, the number should be 13 to follow the +3, +4, +5 pattern.
• Therefore, 14 is the wrong number.
General Intelligence
Number Series
Number Series
Q. #6561 (CAT-I)
Find the missing term in the sequence:
7, 17, 37, 77, ?
A.
157
B.
145
C.
154
D.
158
View Answer & Explanation
• Pattern logic: Each term is obtained by multiplying the previous term by 2 and adding 3:
7 × 2 + 3 = 14 + 3 = 17
17 × 2 + 3 = 34 + 3 = 37
37 × 2 + 3 = 74 + 3 = 77
77 × 2 + 3 = 154 + 3 = 157
• Thus, the missing number is 157.
General Intelligence
Number Series
Number Series
Q. #6560 (CAT-I)
Find the missing number in the series:
2, 2, 1, 4, 4, 6, 8, 8, ?
View Answer & Explanation
• The terms form two alternating series:
Upper/Odd-positioned series (1st, 3rd, 5th, 7th...): 2, 1, 4, 8
Lower/Even-positioned series (2nd, 4th, 6th, 8th, 9th/target in 3-part steps):
Grouping in pairs or alternate streams:
Stream 1 (Positions 2, 4, 6, 8): 2 → 4 → 6 → 8 (+2 at each step)
Stream 2 (Positions 1, 5, 7, 9): 2 → 4 → 8 → ? (multiplying by 2 each step)
2 × 2 = 4
4 × 2 = 8
8 × 2 = 16
• Hence, the required term is 16.
⚡ Practice with real exam timer and negative marking?
Attempt 100-Question Sunday Mega Mock Tests with Live State Rankings.
Free Registration
General Intelligence
Number Series
Number Series
Q. #6559 (CAT-I)
Find the missing number in the following sequence:
36, 34, 30, 28, 24, ?
View Answer & Explanation
• Pattern logic: The differences alternate between subtracting 2 and subtracting 4:
36 - 2 = 34
34 - 4 = 30
30 - 2 = 28
28 - 4 = 24
24 - 2 = 22
• Therefore, the next number is 22.
General Intelligence
Number Series
Number Series
Q. #6558 (CAT-I)
Find the missing term in the following number series:
1, 2, 2, 4, 3, 8, 7, 10, ?
View Answer & Explanation
• The sequence contains two intertwined sub-series:
Even-positioned terms: 2, 4, 8, 10 (differences are +2, +4, +2...)
Odd-positioned terms: 1, 2, 3, 7, ?
1 + 1 = 2
2 + 1 = 3
3 + 4 = 7
7 + 4 = 11
• Hence, the missing term is 11.
General Intelligence
Number Series
Number Series
Q. #6557 (CAT-I)
Find the missing term in the given series:
2, 3, 4, 6, 8, 12, 16, 24, ?
View Answer & Explanation
• The sequence is composed of two alternate geometric progressions:
First series (odd positions): 2, 4, 8, 16, ?
2 × 2 = 4
4 × 2 = 8
8 × 2 = 16
16 × 2 = 32
Second series (even positions): 3, 6, 12, 24
3 × 2 = 6
6 × 2 = 12
12 × 2 = 24
• Therefore, the next term is 32.
General Intelligence
Number Series
Number Series
Q. #6556 (CAT-I)
Find the missing number in the sequence:
7, 12, 22, 42, 82, ?
A.
173
B.
162
C.
183
D.
143
View Answer & Explanation
• Pattern logic: Next term = Previous term × 2 - 2
7 × 2 - 2 = 14 - 2 = 12
12 × 2 - 2 = 24 - 2 = 22
22 × 2 - 2 = 44 - 2 = 42
42 × 2 - 2 = 84 - 2 = 82
82 × 2 - 2 = 164 - 2 = 162
• Alternatively, the differences are 5, 10, 20, 40, 80 (doubling each step):
82 + 80 = 162.
General Intelligence
Number Series
Number Series
Q. #6555 (CAT-I)
Find the missing numbers in the given series:
1, 2, 3, 14, 5, 34, 7, ?, ?
A.
68, 7
B.
63, 9
C.
60, 11
D.
62, 9
View Answer & Explanation
• The given sequence is formed by combining two interleaved series:
First series at odd positions: 1, 3, 5, 7, ?
1 + 2 = 3
3 + 2 = 5
5 + 2 = 7
7 + 2 = 9
• Second series at even positions: 2, 14, 34, ?
2² - 2 = 4 - 2 = 2
4² - 2 = 16 - 2 = 14
6² - 2 = 36 - 2 = 34
8² - 2 = 64 - 2 = 62
• Therefore, the missing numbers are 62 and 9 respectively.
General Intelligence
Number Series
Number Series
Q. #6554 (CAT-I)
Find the missing number in the following series:
12, 8, 14, 6, 16, ?
View Answer & Explanation
• The given sequence consists of two alternating series:
First series: 12 → 14 → 16 (increment of +2)
Second series: 8 → 6 → ? (decrement of -2)
8 - 2 = 4
• Thus, the missing number is 4.
General Intelligence
Number Series
Number Series
Q. #6553 (CAT-I)
Find the missing number in the following series: 6, 13, 34, ?, 286, 853
View Answer & Explanation
• The rule is multiplying the previous term by 3 and subtracting 5:
6 × 3 - 5 = 13
13 × 3 - 5 = 34
34 × 3 - 5 = 102 - 5 = 97
97 × 3 - 5 = 291 - 5 = 286
286 × 3 - 5 = 858 - 5 = 853
• Hence, the missing number is 97.
General Intelligence
Number Series
Number Series
Q. #6552 (CAT-I)
Find the missing number in the sequence: 2, 4, 13, 41, 106, ?
A.
232
B.
172
C.
191
D.
219
View Answer & Explanation
• Analyze the successive differences:
4 - 2 = 2
13 - 4 = 9
41 - 13 = 28
106 - 41 = 65
• Second differences: 9 - 2 = 7, 28 - 9 = 19, 65 - 28 = 37
• Third differences: 19 - 7 = 12, 37 - 19 = 18 (increasing by 6)
• Next third difference: 18 + 6 = 24
• Next second difference: 37 + 24 = 61
• Next first difference: 65 + 61 = 126
• Missing term = 106 + 126 = 232.
General Intelligence
Number Series
Number Series
Q. #6551 (CAT-I)
Identify the incorrect (wrong) number in the sequence: 232, 343, 454, 564, 676
A.
232
B.
343
C.
454
D.
564
View Answer & Explanation
• In all terms except 564, the first (hundreds) and third (units) digits are identical:
In 232: hundreds digit = 2, units digit = 2
In 343: hundreds digit = 3, units digit = 3
In 454: hundreds digit = 4, units digit = 4
In 676: hundreds digit = 6, units digit = 6
• For 564, the hundreds digit is 5 and the units digit is 4 (which should be 565).
• Hence, 564 is the wrong number.
General Intelligence
Number Series
Number Series
Q. #6550 (CAT-I)
Find the wrong number in the following series: 6, 12, 21, 32, 45, 60
View Answer & Explanation
• The differences between consecutive terms should form an arithmetic progression with a common difference of 2:
5 + 7 = 12
12 + 9 = 21
21 + 11 = 32
32 + 13 = 45
45 + 15 = 60
• To maintain this series, the first term should be 5 instead of 6.
• Therefore, 6 is the wrong number.
General Intelligence
Number Series
Number Series
Q. #6549 (CAT-I)
Find the missing number in the following sequence: 7, 19, 42, 87, ?
A.
138
B.
176
C.
173
D.
216
View Answer & Explanation
• The pattern follows multiplying by 2 and adding a decreasing constant:
7 × 2 + 5 = 19
19 × 2 + 4 = 42
42 × 2 + 3 = 87
87 × 2 + 2 = 174 + 2 = 176
• Hence, the correct number is 176.