1. 4, 3, 4, 9, 32 ……

a.125

b. 135

c.145

d. 155

2. 16 (81) 25                 49 (169) 36         64 ( ? ) 4

a. 121

b. 84

c. 81

d. 100

3. 1.5, 3, 5.5, 9, 13.5, 19, …

a. 81

b. 15.5

c. 21.5

d. 25.5

4. Which term of the series 5,8,11,14,…….is  320?

a. 104^th

b. 105^th

c. 106^th

d. 64^th

5. In the series 5, 10, 20, 40,….what will be the 10^th term?

a. 1280

b. 2560

c. 1820

d.  2650

6. QPO, SRQ, UTS, WVU, ?

a. XVZ

b. ZYA

c. YXW

d. VWX

7. deb ijg  nol  ?  xyv

a.rsp

b. stp

c. rsq

d. stq

e. sto

8. AB, DEF, HIJK, ? , STUVWX

a. MNOPQ

b. LMNOP

c. LMNO

d. QRSTU

9. shg rif qje ? olc

a. ole

b. pkd

c. nmc

d. nlb

10. Find the wrong term in the letter-number series given below:

G4T, J10R, M20P, P43N, S90L

a. G4T

b. J10R

c. M20P

d. P43N

e. S90L

Answer & Explanations

1. The numbers are (x*1)-1; (x2)-2; (x3)-3….

    Hence the series would be (32*5)-5=155

2. The pattern is 8² (?) 2²; ?= 8+2=10²= 100

3. The pattern is get by adding 1.5, 2.5, 3.5 …..

    Then, 19+6.5 = 25.5

4. Clearly, 5+3= 8, 8+3= 11, 11+3= 14,….

    So this is an A.P series in which a=5, d=3.

    Let the number of the terms be n

    Then, 320= 5+(n-1)*3; 3n=318; n=106

5. This is an G.P series in which a= 5; r= 2

    10^th term= ar^(n-1) = 5*2 ^(10-1) = 5*2 ⁹ = 2560

6. Each term in the series consists of three consecutive letters in reverse order. The first letter of each term
    and last letter of next term is the same.

7. The letters in each term are moved five steps forward to obtain the corresponding letters of next term.

8. The number of letters in the terms goes on increasing by one at each step. Each term consists of letters
    in alphabetic order. The last letter of each term and first letter of next term are alternate.

9. The first and third letters of each term are moved one step backward and the second letter is moved one
    step forward to obtain the corresponding letters of the next term.

10. The first letter of each term is moved three steps forward and the last letter is moved two steps
     backward to obtain the corresponding letters of the next term. The numbers follow the sequence *2+1,
     *2+2, *2+3, *2+4.

    So, 10 is wrong and must be replaced by (4*2+1) = 9.