Classical

Number Series - Number series MCQ

21:  

4,3,12,9,2,18,3, ...21

A.

5

B.

4

C.

3

D.

7

 
 

Option: D

Explanation :

4x3=12,
9x2=18 and
3x7=21


22:  

78,65,75,62,72...?

A.

61

B.

65

C.

64

D.

59

 
 

Option: D

Explanation :

There are two series78,75,72 and 65,62,59


23:  

6,5,24,25,144,(?)

A.

155

B.

160

C.

170

D.

175

 
 

Option: D

Explanation :

IIIrd term is=Ist termx4,i.e.,6x4=24
IVth term is =IInd term x 5,i.e,5x5=25
Vth term is = IVth termx7,i.e.,25x7=175
Multipliers are in the increasing order of 4,5,6,7, etc


24:  

60,30,120,15,240?

A.

30

B.

120

C.

240

D.

7 1/2

 
 

Option: D

Explanation :

there are two seriee=s 60,120,240 and 30,15,7 1/2 etc.
The terms in the first series are doubling and in the IInd they are being halved


25:  

6,24,60,120,336,(?)

A.

270

B.

240

C.

210

D.

336

 
 

Option: D

Explanation :

There are three groups in the series 6 ---24,60,---120 and 366---366 and ratios are 1:4, 1:2 and 1:1




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