1,3,7,15,31......... 10th term of the sequence will be

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26 Nov 2012 sequence

1,3,7,15,31.........
10th term of the sequence will be

OPtion

1) 1023
2) 511
3) 2047
4) 4095
5) 255
6) 127
7) 8191
8) 63
9) 923
10) none of these

Solution

1 = 2^1-1
3 = 2^2-1
7 = 2^3-1
15 = 2^4-1
31 = 2^5-1
so 10th term = 2^10-1 = 1024-1 = 1023

Correct Option: 1 Best Solution (13)

Balakrishnan M   11 years AGO

'n'th term of the sequence is (2^n)-1
10th term of the sequence is (2^10)-1= 1024-1
= 1023

Like? Yes (7) | No   

Ankit   11 years AGO

1
2+1 =3
4+3 =7
8+7 =15
16+15 =31
32+31 =63
64+63 =127
128+127 = 255
255+256 = 511
511+512 = 1023

Like? Yes (8) | No (2)  

B.Senthil Kumar   11 years AGO

Series goes with difference of powers of 2 so 10th term is 1023

Like? Yes (3) | No (1)  

Sourav   11 years AGO

difference is getting doubled... 2,4,8,16...
so next difference will be 32
thus next is 63.calculating like this we get the series as 1,3,7,15,31,63,127,255,511,1023
10th term is 1023

Like? Yes (2) | No   

Akula Sai Chanukya   11 years AGO

1+1=2+1=3
3+3=6+1=7.
....
...
...
511+511=1022+1=1023

Like? Yes (2) | No   

Ashu Tosh Bhardwaj   11 years AGO

The difference between 1 and 3 = 2
difference between 3 and 7 = 2*(previous diff)
= 2*2 = 4
difference between 7 and 15 = 2*(previous diff)
= 2*4 = 8
difference between 15 and 31 = 2*(previous diff)
= 2*8 = 16
difference between 31 and ? = 2*(previous diff)
= 2*16 = 32
so the next term = 31+32 = 63
so the 10th term = 1023

Like? Yes (1) | No   

lakshmi prasanna   11 years AGO

the sequencs is 1,3,7,15,31,63,127,255,511,1023,2047......
the number =(previous num in sequence+next num of previous num)i,e..31+32=63....
10th term=511+512=1023

Like? Yes (1) | No   

Zakirhusen    11 years AGO

1+2=3
3+4=7
7+8=15
15+16=31
31+32=63
63+64=127
127+128=255
255+256=511
511+512=1023

Answer is 1023 being the 10th Term in the sequence.

Like? Yes (1) | No   

Rodda kiran kumar   11 years AGO

(x*2)+1=y
(y*2)+1=z
and ......................

Like? Yes (1) | No   

satyanarayana   11 years AGO

1,3,7,15,31.63,127,255,511,1023
X*2+1

Like? Yes (2) | No (1)  

PRATHAM MEHROTRA   11 years AGO

next term will be 2*previous term+1
6th term will be 2*31+1=63 ,
7th term will be 2*63+1=127 ,
8th term will be 2*127+1=255 ,
9th term will be 2*255+1=511 ,
10th term will be 2*511+1=1023

Like? Yes (1) | No   

Dushyant Kumar   11 years AGO

1+2=3+(2*2)=7+(4*2)=15 so on

Like? Yes (1) | No (1)  

ankushjain   11 years AGO

1+2=3
3+4=7
7+8=15
15+16=31
similarly
.
.
.
255+256=511
511+512=1023=10th term

Like? Yes (1) | No (2)