Q. In the following number series a wrong number is given. Find out the wrong number.
1, 3, 10, 21, 64, 129, 356, 777
1, 3, 10, 21, 64, 129, 356, 777
✅ Correct Answer: (D)
356
Explanation: The given pattern is,
2nd term → 1*2+1 = 3
3rd term → 3*3+1 = 10
4th term → 10*2+1 = 21
5th term → 21*3+1 = 64
6th term → 64*2+1 = 129
7th term → 129*3+1= 388
So, 7th term 356 is wrong and must be replaced by 388.
Explanation by: Mr. Dubey
The given pattern is,
2nd term → 1*2+1 = 3
3rd term → 3*3+1 = 10
4th term → 10*2+1 = 21
5th term → 21*3+1 = 64
6th term → 64*2+1 = 129
7th term → 129*3+1= 388
So, 7th term 356 is wrong and must be replaced by 388.
2nd term → 1*2+1 = 3
3rd term → 3*3+1 = 10
4th term → 10*2+1 = 21
5th term → 21*3+1 = 64
6th term → 64*2+1 = 129
7th term → 129*3+1= 388
So, 7th term 356 is wrong and must be replaced by 388.