1, 3, 7, 13, 21, 31, ? ? will be

Dr.Dipin Singh   11 years AGO

nth term is given by
1+n*(n-1)
when n=1, term =1+0=1
T2= 1+2*1=3
T3= 1+3*2= 7
..
..
T7 = 1+7*6=1+42=43

Like? Yes (18) | No (8)  

Sukh   11 years AGO

1, 3, 7, 13, 21, 31, ?
1+2=3
3+4=7
7+6=13
..
..
31+12=43

Like? Yes (14) | No (7)  

parul mishra   11 years AGO

option(7)
the sequence is following as.
1^2-0=1
2^2-1=3
3^2-2=7
4^2-3=13
5^2-4=21
6^2-5=31
now 7^2-6=43

Like? Yes (4) | No (2)  

ritesh dhawale   11 years AGO

the diff. between each no. is in the form of 2 4 6 8 10 12 so 31+12=43

Like? Yes (2) | No   

pallavi sahu   11 years AGO

boz the no of diffrence is 6,8,10,12.........

Like? Yes (2) | No   

mahesh   11 years AGO

each number to add +2,+4,+6,+8,+10
then last no. to add +12
then our ans is 43

Like? Yes (3) | No (1)  

A J V   11 years AGO

The difference of the sequence is the multiplication of 2.

Like? Yes (5) | No (5)  

SHUBHAM KARODIYA   11 years AGO

3-1=2
7-3=4
13-7=6
21-13=8
31-21=10
hence next term is 43 as 43-31=12
the diffrence of succesive term form the table of 2.

Like? Yes (1) | No (2)  

Preetha Maniyalath   11 years AGO

2 4 6 8 10
next difference will be 10+2
=12
number 31+12=43

Like? Yes (4) | No (5)  

Balakumaran N.A   11 years AGO

sequence increasing by 2,4,6,8,10,12...

Like? Yes (3) | No (5)  

thangamari   11 years AGO

3-1=2*1
7-3=2*2
13-7=2*3
21-13=2*4
31-21=2*5
x-31=2*6
=>x=12+31
=>x=43

Like? Yes (4) | No (6)  

susmit   11 years AGO

DIFFERENCE IN NUMBERS IS
2,4,6,8,10
SO THE NEXT DIFFERENCE IS 10+2=12
HENCE THE NEXT NUMBER IS 31+12=43.. OPTION NO.7

Like? Yes (3) | No (6)  

sagar arora   11 years AGO

every step multiple of 2 is being added

Like? Yes (2) | No (5)  

SDeep Bhattacharya   11 years AGO

Let's calculate {Tn – T(n-1) } for the given sequence.
Where Tn & T(n-1) respectively are the nth and (n-1)th terms of the given sequence.
Now, clearly calculating {Tn – T(n-1) } for the given sequence we get :
2,4,6,8,10,(T7-31)
So, definitely the next term of the above sequence will be : 12.
Therefore,(T7-31)=12
=>T7=43
So, OPTION 7)43

Like? Yes (2) | No (5)  

Ajay Kashyap   11 years AGO

difference between terms is as: 2,4,6,8,10,12
so next term will be : 31+12 =43

Like? Yes (3) | No (6)  

Narender Bhardwaj   11 years AGO

Given series 1, 3, 7, 13, 21, 31,...
=1+(2+1)+(3+4)+(7+6)+(13+8)+(21+10)+....
Hence next term=31+12=43 ans

Like? Yes (1) | No (5)  

PARAG KAMRA   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43(ans)

Like? Yes (2) | No (6)  

lala   11 years AGO

k(n) = k(n-1) +2(n-1) with k(1) =1
k(7) =k(6) +2(7-1)
k(7) =31 +2*6
k(7) =31+12
k(7) =43

Like? Yes (1) | No (5)  

jyotish r   11 years AGO

the differences of adjacent terms forms the sequence of even numbers 2 4 6 8 10
so next difference=12
so next term in the given sequence is 31+12=43

Like? Yes (2) | No (6)  

ArunKumar   11 years AGO

1
1+2 =3
3+4 =7
7+6=13
13+8= 21
21+10=31
31+12=43

Like? Yes (1) | No (5)  

vishnukarthick   11 years AGO

(7) 43
series 1, 3 ,7 ,13 ,21 ,31
k(n) = k(n-1) +2(n-1) with k(1) =1
k(7) =k(6) +2(7-1)
k(7) =31 +2*6
k(7) =31+12
k(7) =43
seventh term of series is 43

Like? Yes (1) | No (5)  

swati   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43......so..on
each number is added by multiple of 2

Like? Yes (3) | No (7)  

richa   11 years AGO

The difference between each number is of 2's table
1+2=3
3+4=7
7+6=13
so 31+12=43

Like? Yes (1) | No (5)  

Devendra Marghade   11 years AGO

The series is
1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43

Like? Yes (1) | No (5)  

ajitha   11 years AGO

ans:43
1, 3, 7, 13, 21, 31
| | | | | |
1+0^2 2+1^2 3+2^2 4+3^2 5+4^2 6+5^2 ..7+6^2=43
The series is 1,3,7,13,21,31,43...

Like? Yes (1) | No (5)  

Balakrishnan M   11 years AGO

1, 3, 7, 13, 21, 31, ?
difference of the seq is 2,4,6,8,10,..
next term is 31+12=43

Like? Yes (1) | No (5)  

kumara swamy D G   11 years AGO

even numbers(2,4,6,8,10)31+12=43 increasing

Like? Yes (1) | No (5)  

Ganga Prasad Bhusal   11 years AGO

3-1=2
7-3=4
13-7=6
21-13=8
31-21=10
so 43-31=12
hence ANS=7)43

Like? Yes (1) | No (5)  

karthikvarma   11 years AGO

sequence is adding with 2 ,+4,+6,+8
so our answer is 31+12=43

Like? Yes (1) | No (5)  

Vikas Bhutada   11 years AGO

Series increases by multiples of 2's (2, 4, 6, 8, ...)

Like? Yes (1) | No (5)  

krutika patidar   11 years AGO

3-1=2
7-3=4
13-7= 6
21-13=8
31-21=10
so 31+12=43

Like? Yes (1) | No (5)  

Pradeep   11 years AGO

Simply find the differnce between the consequetive integers. Here it comes to be 3-1=2, 7-3=4,21-13=8,31-21=10, therefore next differnce should be of 12 Hence, 31+12=43

Like? Yes (1) | No (5)  

Rakesh Kumar Kohli   11 years AGO

The nth term of the series are
1, 1+2 , 3+4, 7+6, 13+8, 21+10, 31+12=43 ,.....

Like? Yes (1) | No (5)  

birenparekh   11 years AGO

difference between two numbers are 2,4,6,8,10..so next number will be 31+12=43...so ans is option 7

Like? Yes (1) | No (5)  

Leena Sahani   11 years AGO

1+2 = 3
3+4 = 7
7+ 6 = 13
13+ 8 = 21
21+10 = 31
31+12 = 43

Like? Yes (1) | No (5)  

Ashita Kaushik   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43
hence the answer is 43

Like? Yes (1) | No (5)  

phani   11 years AGO

differences:2,4,6,8,10,12,..................

Like? Yes (1) | No (5)  

jagannathan   11 years AGO

there is addition in series starting with +2

Like? Yes (1) | No (5)  

prem kumar.s   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43...
so ans is 43 and option 7th is correct

Like? Yes (2) | No (6)  

VIVEK SINGH   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31 &
31+12=43
every next digit is added by 2,4,6,8,10 so next wil be come by adding 12

Like? Yes (2) | No (6)  

kiran ks   11 years AGO

the successive nums are having differences 2,4,6,8,10 and 12

Like? Yes (1) | No (5)  

ramadevivalli   11 years AGO

the difference is in 2,4,6,8,10,.. sequence
next we have to add 12 to 31 and the answer is 43

Like? Yes (1) | No (5)  

Madhu   11 years AGO

the sequence is,
1+2,3+4,7+6,13+8,21+10,31+12
each is added with multiples of 2.

Like? Yes (1) | No (5)  

Susanta Kar   11 years AGO

as the difference between two subsequent nos are gradually increasing like 2,4,6,8,10.
so next will be 12.
so,no is = 31+12 = 43

Like? Yes (1) | No (5)  

ASWARTHA   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43

Like? Yes (1) | No (5)  

sainath   11 years AGO

the sequence follows T(n+1)=Tn+2*(n)
where Tn is nth term...
so T7=T6+2*(6)=31+12=43...

simply 1,(1+2)=3,(3+4)=7,(7+6)=13,(13+8)=21,(21+10)=31, finally (31+12)=43...

Like? Yes (2) | No (7)  

ABHINAV KUMAR SINHA   11 years AGO

1+2=3
3+4=7
7+6=13
13+8=21
similarly 31+12=43

Like? Yes (1) | No (6)  

TazimAhemad   11 years AGO

Add 2 in increasing manner
1+2=3
3+4=7
7+6=13
13+8=21
21+10=31
31+12=43
So ans is 43

Like? Yes (1) | No (6)