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Direction: In each of these questions a number series is given. Only one number is wrong in each series. You have to find out the wrong number.

  1. 2 , 8 ,32 , 148 , 765 , 4626 , 32431
    1. 765
    2. 148
    3. 8
    4. 32
    5. 4626
Correct Option: D

From the given graph , we can see that the increasing order of series as -
First term = 2
Second term = First term × 2 + 22
Second term = 2 × 2 + 22 = 4 + 4 = 8 ;
Third term = Second term × 3 + 32
Third term = 8 × 3 + 32 = 24 + 9 = 32 ; 32 is wrong. It should be 33.
Similarly , we can find all others terms also.
Fourth term = Third term × 4 + 42
Fourth term = 33 × 4 + 42 = 132 + 16 = 148 ;
Fifth term = Fourth term × 5 + 52
Fifth term = 148 × 5 + 52 = 740 + 25 = 765 ;
Sixth term = Fifth term × 6 + 62
Sixth term = 765 × 6 + 62 = 4590 + 36 = 4626 ;
Seventh term = Sixth term × 7 + 72
Seventh term = 4626 × 7 + 72 = 32382 + 49 = 32431
Hence, 32 is wrong. It should be 33.



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