Number Series Rules with solved Problems
Series is an important chapter from banking examination point of view. Following are some of the important rules or order on which the number series can be made :-
- Pure Series
- Difference Series
- Ratio Series
- Mixed Series
- Geometric Series
- Other Types
1. Pure Series:
In this type of number series, the number itself obeys certain order so that the character of the series can be found out.
The number itself may be.
Perfect Square
Example :
121, 144, 169, 225 ?
Answer - 256
Perfect Cube
Example :
6859, 5832, 4913, 4096, 3375, ?
Answer - 2744
2. Difference Series:
Example :
1348, 1338, 1318, 1288, 1248, ?
Answer - 1198
3. Ratio Series:
Example :
336, 168, 84, 42, 21, ?
Answer - 10.5
4. Mixed Series:
Example :
222, 441, 1321, 2639, 7915, ?
Answer - 15827
5. Geometric Series:
Example 1. 5, 35, 245, 1715, ?
Ans. 12005
Examples 2. 43923,3993, 363, 33, ?
Ans. 3
6. Other Type:
To find the odd number from the number series. In this type of series the above rules are also followed.
Some Examples ;
2, 3, 7, 22, 89, 440, 2677, 18740
Solution : ×1+1, ×2+1, ×3+1, ×4+1, ×5+1 ........
So, 440 is replaced by 446
5, 6, 14, 40, 89, 170, 291
Solution : +12, +32, +52, +72, +92
So, 14 is replaced by 15.
445, 221, 109, 46, 25, 114, 4
Solution : -3÷2, -3÷2........
So,46 is replaced by 53.
12, 26, 56, 116, 244, 498, 1008
Solution : ×2+2, ×2+4 ×2+6, ........
So, 116 is replaced by 118
8, 27, 64, 125, 217, 343
Solution : 23, 33, 43, 53,.....
So, 217 is replaced by 216
