# Logical Reasoning / Number Series Questions and Answers – X

19 questions on “Logical Reasoning / Number Series Questions and Answers” series where you will find different number series questions followed by some number is getting added or subtracted.

You have to identify the missing number in the series.

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## Questions Section

Q1. Next number in the series is:
32, 39 , 40, 47, 48, ??

Ans: 55 i.e. 48 + 7 = 55,
32,
32 + 7 = 39,
39 + 1 = 40,
40 + 7 = 47,
47 + 1 = 48,
48 + 7 = 55,
Logic: This is a simple alternating addition series. In the first number, 7 is added; in the second 1 is added and so on.

Q2. Find the next number in the series is:
20, 9, -2, -13, ??, -35

Ans: -24 i.e. -13 – 11 = -24,
20,
20 – 11 = 9,
9 – 11 = -2,
-2 – 11 = -2,
-2 – 11 = -13 and so on.
Logic: Every number is previous number minus 11 and that is how you can find the middle number or the number at 5th position.

Q3. Next number in the series is:
26, 32 , 40, 46, 54, ??

Ans: 60 i.e. 54 + 6 = 60,
26,
26 + 6 = 32,
32 + 8 = 40,
40 + 6 = 46,
46 + 8 = 54,
54 + 6 = 60
Logic: This is a simple alternating addition series. In the first number, 6 is added; in the second 8 is added and so on.

Q4. Find the next number in the series is:
-984, -976, -968, -960, ??, -944

Ans: -952 i.e. -960 + 8 = -952,
-984,
-984 + 8 = -976,
-976 + 8 = -968,
-968 + 8 = -968,
-968 + 8 = -960 and so on.
Logic: Every number is previous number plus 8 and that is how you can find out the number at 5th position.

Q5. Next number in the series is:
22, 27 , 33, 38, 44, ??

Ans: 49 i.e. 44 + 5 = 49,
22,
22 + 5 = 27,
27 + 6 = 33,
33 + 5 = 38,
38 + 6 = 44,
44 + 5 = 49,
Logic: This is a simple alternating addition series. In the first number, 5 is added; in the second 6 is added and so on.

Q6. Find the missing number in the series:
6, 14, 21, ??, 35, 42

Ans. 28 i.e.(6*4 + 4) = 28,
6*2 + 2 = 14,
6*3 + 3 = 21,
6*4 + 4 = 28,
6*5 + 5 = 35,
6*6 + 6 = 42.
Logic: 1st number *2 + 2 = second, 1st number * 3 + 3 = third, 1st number * 4 + 4 = fourth and so on.

Q7. Find the missing number in the series:
14, 29, 43, ??, 71, 85

Ans. 57 i.e.(14*4 + 1) = 57,
14*2 + 1 = 29,
14*3 + 1 = 43,
14*4 + 1 = 57,
14*5 + 1 = 71,
14*6 + 1 = 85.
Logic: 1st number *2 + 1 = second, 1st number * 3 + 1 = third and so on.

Q8. Find the next number in the series is:
-376, -369, -362, -355, ??, -341

Ans: -348 i.e. -355 + 7 = -348,
-376,
-376 + 7 = -369,
-369 + 7 = -362,
-362 + 7 = -362,
-362 + 7 = -355,
and so on.
Logic: Every number is previous number plus 7 and that is how you can find out the number at 5th position.

Q9. Next number in the series is:
12, 15 , 13, 16, 14, ??

Ans: 17 i.e. 14 + 3 = 17,
12,
12 + 3 = 15,
15 – 2 =13
and
so on i.e. +3 and then -2 in alternate numbers.
Logic: This is a simple alternating addition and subtraction series. In the first pattern, 3 is added; in the second, 2 is subtracted and so on.

Q10. Find the next number in the series is:
-98, -115, -132, -149, ??

Ans: -166 i.e. -149 – 17 = -166,
-98,
-98 – 17 = -115,
-115 – 17 = -132,
-132 – 17 = -132,
-132 – 17 = -149,
and so on.
Logic: Every number is previous number minus 17 and that is how you can identify the last number in the series.

Q11. Here is the number series to solve, if:
40 + 99 = 5560
85 + 48 = 11305
28 + 2 = 840
39 + 87 = ? – what will be the number here?

40*(40 + 99) = 5560,
85*(85 + 48) = 11305,
28*(28 + 2) = 840,
Logic: The logic is addition of both number multiplied by first number i.e.(40 + 99)*40=5560.

Q12. What is the next number in the series:
98, 49.0, 24.5, 12.25, ?

Logic: Second number is half of first one, 3rd number is half of second one and so on i.e.
98/2 =49.0,
49.0/2 =24.5,
24.5/2 =12.25
and so on.

Q13. Guess next number in the series:
4, 16, 64, 256, ?

Logic: The series is square, cube, ^4 and so on i.e.
4 * 4 = 16 ,
4 * 4 * 4 = 64 etc.

Q14. Guess next number in the series:
1, 2, 4, 7, ?

Ans. 11 i.e. 7 + 4,
Second number is (1st number + 1),
third number is (2nd number + 2),
4th is (3rd number + 3) and so on.
i.e. 1 + 1 = 2,
2 + 2 = 4,
4 + 3 = 7
and so on.

Q15. What will be the next number in the series:
7, 9, 13, 19, ?

Ans. 27 i.e. 12 + 8,
Second number is (1st number + 2),
third number is (2nd number + 4),
4th is (3rd number + 6)
and so on.
7 + 2 = 9,
9 + 4 = 13,
13 + 6 = 19
and so on.

Q16. Find the missing number in the series:
14, 16, ??, 26, 34

Ans. 20 i.e. 16 + 4,
14 + 2 = 16,
16 + 4 = 20,
20 + 6 = 26,
26 + 8 = 34
and so on.
Logic: Second number is (1st number + 2), third number is (2nd number + 4), 4th is (3rd number + 6) and so on.

Q17. Identify the missing number in the series:
22, 25, ?? , 34, 40, 47

Ans. 29 i.e. 25 + 4,
22 + 3 = 25,
25 + 4 = 29,
29 + 5 = 34,
34 + 6 = 40,
40 + 7 = 47.
Logic: First number + 3 = 2nd number, second number + 4 = 3rd number, third number + 5 = 4th number and so on.

Q18. Find the missing number in the series:
20, 20, ??, 120, 480, 2400

Ans. 40 i.e. 20*2 = 40,
20*1 = 20,
20*2 = 40,
40*3 = 120,
120*4 = 480,
480*5 = 2400.
Logic: First number1 = 2nd number, second number2 = 3rd number, third number*3 = 4th number and so on.

Q19. Find the missing number in the series:
0, 2, 3, ??, 5, 6

Ans. 4
Logic: Normal series where number is increasing by 1.

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