Sequence and Series Questions and Solutions : Logical Reasoning

1.

What will be the next term in? 
ZAM, YBL, ----, WDJ, VEI

   A.) XCK
   B.) UFH
   C.) ZAC
   D.) PFD

Answer: Option 'A'

XCK

2.

Find the missing number in the following series. 
2, 3, 6, 15, 45, ?

   A.) 95
   B.) 105.5
   C.) 147
   D.) 157.5

Answer: Option 'D'

2 × 1.5 = 3 
3 × 2 = 6 
6 × 2.5 = 15 
15 × 3 = 45 
45 × 3.5 = 157.5

3.

Look at this series: 3, 4, 7, 8, 11, 12, . . . 
What number should come next ?

   A.) 7
   B.) 10
   C.) 15
   D.) 20

Answer: Option 'C'

This alternating addition series begins with 3;
then 1 is added to give 4;
then 3 is added to give 7;
then 1 is added, and so on.
Rule = (first number + 1) (second number + 3) (third number + 1) (fourth number + 3)...
Now The series is 3, 4, 7, 8, 11, 12...
(3 + 1 = 4), (4 + 3 = 7), (7 + 1 = 8), (8 + 3 = 11), (11 + 1 = 12) (12 + 3 = 15)...
So the answer is d = 15.

4.

3 13 18 23 28 33
What number should come next?

   A.) 38 43
   B.) 37 42
   C.) 38 44
   D.) 39 44

Answer: Option 'A'

In this simple addition series, each number is 5 greater than the previous number.
Rule = (1st no) (1st no + 5 = 2nd no) (2nd no + 5 = 3rd no) . . .
Now (3) (3 + 5 = 8) (8 + 5 = 13) (13 + 5 = 18) (18 + 5 = 23) (23 + 5 = 28) (28 + 5 = 33) (33 + 5 = 38) (38 + 5 = 43)
So the answer is c = 38 43

5.

Find the missing number in the following series. 
376, 188, 47, 23.5, ?

   A.) 7.8
   B.) 6.5
   C.) 5.8
   D.) None of these

Answer: Option 'C'

367/2 = 188 
188/4 = 47 
47/2 = 23.5 
23.5/4 = 5.8

Sequence and Series Download Pdf