Learn and practice the chapter "Number Series" with these solved Logical Reasoning Questions and Answers. Each question in the topic is accompanied by a clear and easy explanation, diagrams, shortcuts and tricks that help in understanding the concept.

Use of Number Series

The questions and examples given in this section will be useful to all the freshers, college students and engineering students preparing for placement tests or any competitive exam like MBA, CAT, MAT, SNAP, MHCET, XAT, NMAT, GATE, Bank exams - IBPS, SBI, RBI, RRB, SSB, SSC, UPSC etc.

Practice with this online test to ensure that you get through your placements and entrance tests with flying colours!

1. What are next two letters in the given series?
E F H K O ? ?

a. TZ
b. SY
c. SX
d. RW

Answer: a. TZ

Explanation:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Here the next alphabet skips alphabets in increasing order of 0, 1, 2, 3, etc.

After E, 0 alphabets skipped. So, we get F which is immediately next.

After F, 1 alphabet skipped. So, we skip G which is next and get H.

After H, 2 alphabets skipped. So, we skip I J and get K.

After K, 3 alphabets skipped. So, we skip L M N and get O.

After O, 4 alphabets skipped. So, we skip P Q R S and get T.

After T, 5 alphabets skipped. So, we skip U V W X Y and get Z.

2. Find the next in the sequence
5, 21, 69, 213, 645, ?

a. 1935
b. 1815
c. 1941
d. 1290

Answer: c. 1941

Explanation:

5
5 x 3 + 6 = 21
21 x 3 + 6 = 69
69 x 3 + 6 = 213
213 x 3 + 6 = 645
645 x 3 + 6 = 1941

3. If first 10 alphabets of the alphabet series are written in reverse then what will come next in the given sequence
JZMY, IXLW, HVKU, ?

a. FSIS
b. GTAS
c. GSBT
d. GTIS

Answer: b. GTAS

Explanation:

Alphabet Series - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
1^{st} 10 alphabets Reversed - J I H G F E D C B A K L M N O P Q R S T U V W X Y Z
The reversed series should be taken for finding the answer.
The first letter goes up by 1 i.e. J I H. So next is G
The third letter goes down by 1 i.e. M L K. So next is A.
2^{nd} and 4^{th} letters skip one letters.
So 2^{nd} letter is T and 4^{th} will be S.
Answer = GTAS

4. Fill the blanks
bof _cb _fcc _ofc _bo _ cc

a. f o c c f
b. f o c c b
c. c o f c f
d. c o b c f

Answer: d. c o b c f

Explanation:

Here we need to observe small patterns and then write the answer.

In first 3 alphabets, we see that o comes before f. So, 2^{nd} blank has to be o.

c comes before b. So 4^{th} blank has to be c.

f comes before cc. So last blank has to be f.

cc comes after f. So 1^{st} blank needs to be c to satisfy this condition.