2,9,28,65,126,...... next number will be

M4maths Previous Puzzles

12 Sep 2011 sequence

2,9,28,65,126,......
next number will be

OPtion

1) 195
2) 198
3) 200
4) 208
5) 210
6) 215
7) 217
8) 256
9) 299
10) none of these

Solution

2 = 1^3 + 1
9 = 2^3 + 1
28 = 3^3 + 1
similarly

Correct Option: 7 Best Solution (14)

Dr.Dipin Singh   12 years AGO

nth term n^3+1
1st term = 1^3+1=2
2nd term = 2^3+1=9
3rd term = 3^3+1=28
4th term = 4^3+1=65
5th term = 5^3+1=126
6th term = 6^3+1=217 ... option 7

Like? Yes (46) | No (10)  

dharmaveer   12 years AGO

2 * 1 = 2
3 * 3 = 9
4 * 7 = 28
5 * 13 = 65
6 * 21 = 126

The second factors increase by 2, 4, 6, 8, so the next increase must be 10, giving 31.

7 * 31 = 217

so, option 7

Like? Yes (16) | No (7)  

Soumya Parhi   12 years AGO

the ans is 217..
The series is 2,9,28,65,126,___
i.e 1^3+1,2^3+1,3^3+1,4^3+1,5^3+1,6^3+1=217
the series is of the form n^3+1,where n=1,2,3,4,5,6.

Like? Yes (5) | No   

Balakumaran N.A   12 years AGO

1^3+1, 2^3+1,3^3+1, 4^3+1,....5^3+1,(6^3)+1=217 is the answer...

Like? Yes (6) | No (2)  

Saranjit Singh   12 years AGO

1^3+1=2
2^3+1=9
..
..
6^3+1=216+1=217

Like? Yes (5) | No (1)  

Prerna   12 years AGO

1^3+1= 2
2^3+1=9
..
..
6^3+1=216+1=217 .. option 7

Like? Yes (6) | No (2)  

susmit   12 years AGO

formula is (x*x*x)+1
so (6*6*6)+1=217

Like? Yes (6) | No (3)  

Ratika Goyal   12 years AGO

cube of natural nos + 1 is the logic
1^3+1=2
2^3+1=9
3^3+1=28
4^3+1=65
5^3+1=126
6^3+1=217

Like? Yes (3) | No (2)  

virendra   12 years AGO

1^3+1=2
2^3+1=9
so...
6^3+1=217

Like? Yes (2) | No (2)  

soumya goyal   12 years AGO

1^3+1=2
2^3+1=9
3^3+1=28
4^3+1=65
5^3+1=126
6^3+1=217
hence option 7 is correct

Like? Yes (4) | No (4)  

@SI-IW@NI 12U13EY   12 years AGO

given series is 2,9,28,65,126,........
here, first term=(1^3)+1=2
second term=(2^3)+1=9
third term=(3^3)+1=28
fourth term=(4^3)+1=65
fifth term=(5^3)+1=126
since here nth term of series=(n^3)+1
so, the sixth term would be=(6^3)+1=217
hence 7 is the correct choice

Like? Yes (3) | No (3)  

atmakuri jagadish   12 years AGO

2*1 = 2
3*3 = 9
4*7 = 28
5*13 = 65
6*21 = 126....so
7*31 = 217

Like? Yes (7) | No (8)  

~Sandeep~   12 years AGO

n^3+1 Series
For n=6, 6^3+1 = 217

Like? Yes (3) | No (5)  

Perumal Natarajan   12 years AGO

1^3+1=2
2^3+1=9
3^3+1=28
4^3+1=65
5^3+1=126
6^3+1=217

Like? Yes (1) | No (3)