Logical Reasoning in English SERIES COMPLETION

Chapter Wise Logical Reasoning in English SERIES COMPLETION

1 >>complete the series

1, 3, 4, 8, 15, 27, ? ?

• (A) 45
• (B) 50
• (C) 55
• (D) 60

Solution The Sum of any three consecutive terms of the series given to the next term.So, missing number = 8 + 15 + 27 = 50.

2 >>complete the series

28, 33, 31, 36, -----, 39? ?

• (A) 30
• (B) 32
• (C) 33
• (D) 34

Solution The pattern is + 5, - 2, + 5, - 2, ....So missing term = 36 - 2 = 34.

3 >>complete the series

0.5, 0.55, 0.65, 0.8? ?

• (A) 0.7
• (B) 0.9
• (C) 0.95
• (D) 1

Solution The pattern is + 0.05, + 0.10, + 0.15, .....So, missing term = 0.8 + 0.20 = 1.

4 >>complete the series

1, 4, 27, 16, ?, 36, 343 ?

• (A) 50
• (B) 78
• (C) 125
• (D) 132

Solution Clearly, the given series consists of cubes of odd numbers and square of even numbers i.e., 1*1*1, 2*2, 3*3*3 4*4, .....So, missing term = 5*5*5 = 125.

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5 >>complete the series

6, 11, 21, 36, 56, ? ?

• (A) 41
• (B) 51
• (C) 71
• (D) 81

Solution The pattern is + 5, + 10, + 15, + 20,....So, missing term = 56 + 25 = 81.

6 >>complete the series

13, 35, 57, 79, 911, ? ?

• (A) 1113
• (B) 1315
• (C) 1110
• (D) 1140

Solution The terms of the given series are numbers formed by joining together consecutive odd numbers in order.i.e. 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11,.....So, missing term = number of formed by joining 11 and 13 = 1113.

7 >>complete the series

1, 4, 9, 16, 25, ? ?

• (A) 24
• (B) 36
• (C) 41
• (D) 43

Solution The numbers are 1*1, 2*2, 3*3, 4*4, .... So missing number = 6*6 = 36.

8 >>complete the series

10, 14, 26, 42, 70, ? ?

• (A) 100
• (B) 102
• (C) 106
• (D) 114

Solution Each term of the series, except the first two terms, is 2 more than the sum of the preceding two terms So,missing term = (42 + 70 ) + 2 = 114.

9 >>complete the series

1, 9, 25, 49, 81, ? ?

• (A) 103
• (B) 112
• (C) 121
• (D) 144

Solution The series consists of squares of consecutive odd numbers i.e. 1*1, 3*3, 5*5, 7*7, 9*9,.....So, missing term = 11*11 = 121.

10 >>complete the series

1, 9, 25, 49, ?, 121 ?

• (A) 72
• (B) 76
• (C) 78
• (D) 81

Solution The given series consists of squares of consecutive odd numbers.i.e. 1*1, 3*3, 5*5, 7*7, 9*9,....So, missing term = 9*9 = 81.

11 >>complete the series

5, 6, 9, 15, ?, 40 ?

• (A) 21
• (B) 23
• (C) 25
• (D) 27

Solution The pattern is + 1, + 3, + 6,.....i.e. + 1, + (1 + 2), + ( 1 + 2 + 3),....So missing term = 15 + ( 1 + 2 + 3 + 4 ) = 25.

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12 >>complete the series

120, 99, 80, 63, 48, ? ?

• (A) 32
• (B) 35
• (C) 38
• (D) 39

Solution The pattern is - 21, - 19, - 17, - 15,.......So, missing term = 48 - 13 = 35.

13 >>complete the series

4, 10, ?, 82, 244, 730 ?

• (A) 24
• (B) 28
• (C) 77
• (D) 218

Solution Each number in the series is 2 less than thrice the preceding number.So missing number = ( 10 *— 3 ) - 2 = 28.

14 >>complete the series

2, 2, 5, 13, 28, ? ?

• (A) 47
• (B) 49
• (C) 50
• (D) 52

Solution The pattern is + 0, + 3, + 8, + 15, .....i.e. + ( 1*1 - 1 ), + ( 2*2 - 1 ), + ( 3*3 - 1 ) + ( 4*4 - 1 ),... So, missing term = 28 + ( 5*5 - 1) = 28 + 24 = 52.

15 >>complete the series

66, 36, 18, ? ?

• (A) 3
• (B) 6
• (C) 7
• (D) 8

Solution Each term in the series is the product of the digits of the preceding term.So, missing term = 1 * 8 = 8.

Logical Reasoning in English

16 >>complete the series

5, 2, 7, 9, 16, 25, ? ?

• (A) 41
• (B) 43
• (C) 45
• (D) 48

Solution Each term in the series, except the first two terms, is the sum of the preceding two terms.So, missing term = 16 + 25 = 41.

17 >>Find the missing number in the series.

5760, 960, ? , 48, 16, 8 ?

• (A) 240
• (B) 192
• (C) 160
• (D) 120

Solution First number is divided by 6 to get the second and the second is divided by 5 to get the third and the third is divided by 4 to get the fourth number and so on.i.e, 5760 / 6 = 960960 / 5 = 192192 / 4 = 4848 / 3 = 1616 / 2 = 8.

18 >>Find the missing number in the series.

3, 9, 21, 39, ? ?

• (A) 72
• (B) 53
• (C) 63
• (D) 51

Solution The numbers progressively increase by multiples of 6. Thus, the difference between 9 and 3 is 6, between 21 and 9 is 12, between 39 and 21 is 18.

19 >>Find the missing number in the series.

1, 0, 3, 2, 5, 4, ? ?

• (A) 9
• (B) 8
• (C) 10
• (D) 7

Solution There are 2 series here. One is 1, 3, 5, 7. The second is 0, 2, 4, 6.

20 >>Find the missing number in the series.

1, 1, 2, 3, 5, 8, 13, ? ?

• (A) 17
• (B) 21
• (C) 23
• (D) 19

Solution Starting from 2, each number is the sum of preceding 2 numbers. Thus 1 + 1 = 2 + 1 = 3 + 2 = 5 + 3 = 8 + 5 = 13 + 8 = 21. 1.e, 1 + 1 = 2 1 + 2 = 3 2 + 3 = 5 3 + 5 = 8 5 + 8 = 13 8 + 13 = 21