What is the next number of the following sequence 1, 3, 6, 10, 15, ......

Kushagra Tiwari   10 years AGO

It's simply the triangular numbers:
1=1
1+2=3
1+2+3=6
1+2+3+4=10
and so on.
You could use the formula n(n+1)/2
to determine the nth triangular
number (ie the sum of the first n
numbers)

Like? Yes (25) | No (2)  

prem kumar   10 years AGO

3-1=2
6-3=3
10-6=4
15-10=5
so next number difference must be 6
so x-15=6
There fore x=21
None of the above

Like? Yes (8) | No (1)  

S.SHAFI   10 years AGO

1,3,6,10,15....

1 + 2 = 3
3 + 3 = 6
6 + 4 = 10
10 + 5 = 15
15 + 6 = 21....

Like? Yes (5) | No   

Sourojit Dhua   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
Hence the next number should be 21 which is not in option. Besides;
This is the Triangular Number Sequence: 1, 3, 6, 10, 15, 21, 28, 36, 45, ... This sequence is generated from a pattern of dots which form a triangle.

Like? Yes (4) | No   

NAVEEN KUMAR   10 years AGO

1=1
1+2=3
1+2+3=6
1+2+3+4=10
1+2+3+4+5=15
1+2+3+4+5+6=21

Like? Yes (3) | No   

Aastha   10 years AGO

next no. will be 21
as difference between two no is in the increasing order
3-1=2
6-3=3
10-6=4
15-10=5
21-15=6

Like? Yes (5) | No (2)  

lakshmi nalluri   10 years AGO

21 will be next in the sequence

Like? Yes (2) | No   

santosh kumar patel   10 years AGO

1
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
hence ans:none of these

Like? Yes (2) | No   

Sandeep mishra   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
so 21 is correct answer

Like? Yes (2) | No   

Rittik Mondal   10 years AGO

1
1+2 = 3
3+3 = 6
6+4 = 10
10+5= 15
15+6= 21;
so next number should be 21

Like? Yes (2) | No   

BHASKAR MANDAL   10 years AGO

it is of the form n(n+1)/2
1(2)/2 = 1
2*3/2 = 3
3*4/2 = 6
4*5/2 = 10
5*6/2 = 15
6*7/2 = 21

so the next number will be 21
option will be none of these

Like? Yes (1) | No   

Sanchit Kapoor   10 years AGO

Each succeeding number is obtained by adding consecutive natural number starting from 2 to the previous number
3=1+2
6=3+3
10=6+4
15=10+5 and so the next number should be 15+6=21
so option 10 none of these is correct.

Like? Yes (3) | No (2)  

vinit   10 years AGO

1,1+2=3,3+3=6,6+4=10,10+5=15,15+6=21;
so it should be 21 hence non of these

Like? Yes (1) | No   

Gitanjali K   10 years AGO

next no. should be 21

Like? Yes (2) | No (1)  

Ravi Bhalani   10 years AGO

next number should be 21

Like? Yes (1) | No   

vartika    10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

dhanaseelan   10 years AGO

As per the sequence the answer must be 21

Like? Yes (1) | No   

Udhaya kumar   10 years AGO

addition of 2,3,4,5,6 respectively.........

Like? Yes (1) | No   

Udaybhan Viswkarma   10 years AGO

This is the Triangular Number Sequence:

1, 3, 6, 10, 15, 21, 28, ....

So, x(n) = n(n+1)/2
x(6)=6(6+1)/2
x(6)=21

Like? Yes (1) | No   

Pratik sharma   10 years AGO

i think difference is going like 2,3,4,5 ..so next term should be 21

Like? Yes (1) | No   

Kunal Jaiswal   10 years AGO

21 should be answer. So none of these.

Like? Yes (1) | No   

~Sandeep~   10 years AGO

This is the Triangular Number Sequence: 1, 3, 6, 10, 15, 21, 28, 36, 45,

Like? Yes (1) | No   

Chandra chur anand   10 years AGO

each no. is incremented by +1
like 1 then
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
so 21 ll be right ans

Like? Yes (1) | No   

DEEPAK GOSWAMI   10 years AGO

the difference is .. 2 , 3, 4, 5, 6 resp.

Like? Yes (1) | No   

kumar   10 years AGO

21

Like? Yes (1) | No   

prabhat   10 years AGO

1
1+2=3
3+3=6
6+4=10
then 15+6=21

Like? Yes (1) | No   

anupriya sinha   10 years AGO

1+2 =3
3+3=6
6+4 =10
10+5=15
15+6=21
21+7=28
28+9=37
and so on

Like? Yes (1) | No   

Abhishek Vishwakarma   10 years AGO

It's simply the triangular numbers:
1=1
1+2=3
1+2+3=6
1+2+3+4=10
and so on.
You could use the formula n(n+1)/2
to determine the nth triangular
number (ie the sum of the first n
numbers)

Like? Yes (1) | No   

Shashank Kapoor   10 years AGO

the number should be 21 as going by the series,as it is not there so answer is option 10 none of these..

Like? Yes (1) | No   

PAWAN KUMAR   10 years AGO

The next no will be 21.
1+2 = 3+3 = 6+4 =10+5 = 15+6 21 Ans.

Like? Yes (1) | No   

Sukanya   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Jigyasa Kumar   10 years AGO

it is the triangular sequence 21, then 28, ....

Like? Yes (1) | No   

Chirag Ranjan Lahiri   10 years AGO

Simple, it must be 21 which is not in option, so ans - 10

Like? Yes (2) | No (1)  

abhilasha   10 years AGO

it is the triangular sequence 21, then 28, ....

Like? Yes (1) | No   

shreya sagar   10 years AGO

ans:(10)none of these
because next term is 21
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

khushboo goenka   10 years AGO

21.
coz diff b/w each no is 2,3,4,5
so 3+3=6,6+4=10, 10+5=15,15+6=21

Like? Yes (1) | No   

Anitha   10 years AGO

Answer is 21, 1+2=3, 3+3=6, 6+4=10, 10+5=15, Answer - 15+6=21

Like? Yes (1) | No   

ragini   10 years AGO

answer 21 ... 1+2=3+3=6+4=10+5=15+6=21+7=28+.....

Like? Yes (1) | No   

pankaj   10 years AGO

since the difference between the consecutive numbers is sequencially increasing. thats why the next no. comes out to be 21 which is not from the above mentioned options......

Like? Yes (1) | No   

Supriya_kamkar   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
ans:21

Like? Yes (1) | No   

Manish kumar   10 years AGO

diff b/w 1 & 3=2
3&6=3
6&10=4
10&15=5
then next is 6
ans = 15+6=21

Like? Yes (1) | No   

Nithin Kumar   10 years AGO

1
1+2=3
1+2+3=6
1+2+3+4=10
1+2+3+4+5=15
1+2+3+4+5+6=21

Like? Yes (1) | No   

Ankit Pandey   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
So next term
15+6=21

Like? Yes (1) | No   

VIMALRAJ V   10 years AGO

The given series is a triangular series. Therefore the next number must be 21, it is not present in the option so answer is NONE OF THESE

Like? Yes (1) | No   

Mahesh   10 years AGO

10+5=15
15+6=21
so, 21 is the answer

Like? Yes (1) | No   

Neel Patel   10 years AGO

Option 10

Like? Yes (1) | No   

SAURISH KAR   10 years AGO

The difference bteween every consecutive number increases by 1

Like? Yes (1) | No   

mithilesh kumar   10 years AGO

since the diffrence b/w two consecutive no is in increasing order i.e 2,3,4,5,so next is =6
so no is=15+6=21

Like? Yes (1) | No   

ramakrishnateja   10 years AGO

the series is given as follows. 1,3,6,10,15.......... the next number after 15 is 21 the difference of the terms are
3-1=2
6-3=3
10-6=4
15-10=5
21-15=6.
so the number is 21.

Like? Yes (1) | No   

Perumal   10 years AGO

1, 1+2=3,1+2+3=6,1+2+3+4=10,1+2+3+4+5=15,1+2+3+4+5+6=21

Like? Yes (1) | No   

Albin Mathew   10 years AGO

the correct answer is 21.Because the differences between consecutive terms is in the progression:2,3,4,5,6.................

Like? Yes (1) | No   

SAI TEJA   10 years AGO

0+1=1
1+2=3
3+3=6
6+4=10
10+5=15

Like? Yes (1) | No   

jalaj   10 years AGO

In each of these numbers difference betwwen each digit is increasing So the next number in the sequence is 21(Hence option 10)
Ex 1 3 diff 2
3 6 diff 3
6 10 diff 4
10 to 15 diff 5
15 to 21 dii 6

Like? Yes (1) | No   

RADHA RANI   10 years AGO

no answer is matching

Like? Yes (1) | No   

Surit Datta   10 years AGO

It's simply the triangular numbers:
1=1
1+2=3
1+2+3=6
1+2+3+4=10
1+2+3+4+5=15
1+2+3+4+5+6=21
or the sequence n(n+1)/2 where n=1,2,3,.....
That's it..

Like? Yes (1) | No   

archanarao rane   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

mamta garkoti   10 years AGO

it should be 21

Like? Yes (1) | No   

Anusha   10 years AGO

ans is 21
1
1+2=3
1+2+3=6
1+2+3+4=10
1+2+3+4+5=15
1+2+3+4+5+6=21

Like? Yes (1) | No   

Anand Dwivedi   10 years AGO

1=1
1+2=3
1+2+3=6
1+2+3+4=10
1+2+3+4+5=15
1+2+3+4+5+6=21

So Answer Will be 21

Like? Yes (1) | No   

Rounak Jain   10 years AGO

Ans is 21. 0+1=1, 1+2=3, 3+3=6, 6+4=10, 10+5=15 so 15+6=21.

Like? Yes (1) | No   

niraj   10 years AGO

1,3,6,10,15,?
3-1=2
6-3=3
10-6=4
15-10=5
x-15=6
x=21(ans)

Like? Yes (1) | No   

saimeera   10 years AGO

1+ 2 =3
3+ 3 =6
6+ 4 =10
10+ 5 =15
15+ 6 =21

NONE OF THESE (21)

Like? Yes (1) | No   

sindhu   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

ankit   10 years AGO

differ 2 ,3,4,5 then 6
ans 21

Like? Yes (1) | No   

priyanka   10 years AGO

3-1=2
6-3=3
10-6=4
15-10=5
21-15=6
sequence number is answer,each number difference is sequence numbers

Like? Yes (1) | No   

Pravena   10 years AGO

answer is 21

Like? Yes (1) | No   

PALASH JAIN   10 years AGO

answer should be 21

Like? Yes (1) | No   

csemalli   10 years AGO

answer is 21

it is first n natural numbers sum

Like? Yes (1) | No   

surya   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
this option not there in options

Like? Yes (1) | No   

Durgesh Tripathi   10 years AGO

Correct Answer =21
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Akash Dhananjay Pahurkar    10 years AGO

First we added 2 then 3 then 4,5.
Then 15+6=21

Like? Yes (1) | No   

upasana acharya   10 years AGO

no increasing by 1,2,3,4.... so on

Like? Yes (1) | No   

shubham tyagi   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Pallab Das   10 years AGO

1+ 3+ 6+ 10 +15 +21
2 3 4 5 6

Like? Yes (1) | No   

Dr.Dipin Singh   10 years AGO

15+6=21

Like? Yes (1) | No   

v pavan   10 years AGO

15+6=21
1+2=3
3+3=6
6+4=10
10+5=15

Like? Yes (1) | No   

Bidulata   10 years AGO

difference is in a sequence of 2 3 4 5 6

Like? Yes (1) | No   

Ritika Shrivastava   10 years AGO

1,3,6,10,15
Next no is 21
1+2=3
3+3=6
6+4=10
10+5=15
So 15+6=21
Next no is 21
Option 10

Like? Yes (1) | No   

Sagar Kumar Subudhi   10 years AGO

3-1=2
6-3=3
10-6=4
15-10=5
similarly next difference should be 6, so 15+6=21
but no in the options so ans is option 10(none of these)

Like? Yes (1) | No   

shekhar suman   10 years AGO

1,3,6,10,15,.....
1+2=3
3+3=6
6+4=10
10+5=15
so
15+6=21 ans

Like? Yes (1) | No   

Amit   10 years AGO

diffrences are 2 3 4 5 6

Like? Yes (1) | No   

siddhartha sadhu   10 years AGO

(1) 2 (3) 4 5 (6) 7 8 9 (10) 11 12 13 14 (15) 16 17 18 19 20 (21).
the number with in the bracket is given . so the next number is 21.

Like? Yes (1) | No   

Sumeet Gupta   10 years AGO

Next will be 21

Like? Yes (1) | No   

AAKANCHA SRIVASTAV   10 years AGO

15+6=21

Like? Yes (1) | No   

MUKESH YADAV   10 years AGO

it would be 21

Like? Yes (1) | No   

satyam shivam   10 years AGO

It's simply the triangular numbers:
1=1
1+2=3
1+2+3=6
1+2+3+4=10

and so on.

Like? Yes (1) | No   

swapnil saxena   10 years AGO

diff is 2,3,4,5, then 6 =21

Like? Yes (1) | No   

vinay kumar m   10 years AGO

ans is 21(15+6)

Like? Yes (1) | No   

vishal shanker polowalia   10 years AGO

diference of 2,3,4,5 and 6 so on
so next nomber is 21

Like? Yes (1) | No   

ganesh babu   10 years AGO

1,1+2=3,3+3=6,6+4=10,10+5=15,15+6=21

Like? Yes (1) | No   

Abhirup Kundu   10 years AGO

difference is 2,3,4,5 and so on

Like? Yes (1) | No   

Shuja Malik   10 years AGO

21 will be the answer

Like? Yes (1) | No   

RISHABH RAJ   10 years AGO

3-1=2, 6-3=3, 10-6=4, 15-10=5 so next difference will be 6 ...i.e 15+6 =21..which is not available

Like? Yes (1) | No   

tirupathi reddy   10 years AGO

The diff is 2,3,4,5,6...
21 is answer

Like? Yes (1) | No   

Shaily Aggarwal   10 years AGO

should be 21

Like? Yes (1) | No   

sirisha   10 years AGO

the order is 1+2=3,3+3=6,------,15+6=21
there is no 21 present

Like? Yes (1) | No   

pawan kumar   10 years AGO

Next no. should be : 15+6=21

Like? Yes (1) | No   

CHANDAN KUMAR   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Piyush   10 years AGO

The ans is 21
There is increasing difference between the no's
1, 3, 6, 10...
So between 1 and 3, 2 is the only no
So one no
Then between 3 and 6
Two no are present 4 and 5
And the process is repeated

Like? Yes (1) | No   

Komala.G   10 years AGO

1
1+2 =3
3+3 =6
6+4 =10
10+5 = 15
15+6 =21

Like? Yes (1) | No   

ravi   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6+21

Like? Yes (1) | No   

RenukaDevi   10 years AGO

answer is 21 bcz sequence is like
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Arpit Jain   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
So answer is 10) None of these

Like? Yes (1) | No   

Yugandhara Shete   10 years AGO

1
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21
non of these

Like? Yes (1) | No   

rajeev chaubey   10 years AGO

1,3,6,10,15,21

Like? Yes (1) | No   

Deepika Dubey   10 years AGO

the ans will be 21
1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

ankit tiwari   10 years AGO

3-1=2
3=(2+1)=6
6-3=3
6+(3+1)=10
a it is
ans shud be 21

Like? Yes (1) | No   

priyanka sharma   10 years AGO

1-3=2
6-3=3
10-6=4
15-x=5

Like? Yes (1) | No   

Sakshi Agarwal   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21 (option not given)

Like? Yes (1) | No   

Aritra Chatterjee   10 years AGO

+2 +3 +4 .....

Like? Yes (1) | No   

MANU   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21;
ans is 21

Like? Yes (1) | No   

ravi prakash   10 years AGO

1+2=3
3+3=6
6+4=10
10+5=15
15+6=21

Like? Yes (1) | No   

Puspendu Bhowmick   10 years AGO

1st increses by 2 then 3
so ans is 21

Like? Yes (1) | No   

Grishma Shah   10 years AGO

Answer is 21 which is not given in list.

1
3 = 1 +2
6 = 3 +3
10 = 6 +4
15 = 10 +5
21 = 15 +6

Like? Yes (1) | No   

nehasrivastava   10 years AGO

21 should be the answer

Like? Yes (1) | No   

KIRANKUMAR AMBATI   10 years AGO

since the answer is 211123123612345621

Like? Yes (1) | No   

narapureddyyallareddy   10 years AGO

15621so non of the options

Like? Yes (1) | No   

anuj gupta   10 years AGO

21

Like? Yes (1) | No   

Ankit   10 years AGO

21

Like? Yes (1) | No   

harshit gupta   10 years AGO

21

Like? Yes (1) | No   

ilamparithi   10 years AGO

12333664101051515621

Like? Yes (1) | No   

Priyam   10 years AGO

12333664101051515621

Like? Yes (1) | No   

Ravi Kumar   10 years AGO

01112333664101051515621ans none of these

Like? Yes (1) | No   

bikash tiwari   10 years AGO

21 is the right answer

Like? Yes (1) | No   

Souvik Basak   10 years AGO

3-12 6-3310-6415-10521-615

Like? Yes (1) | No   

rakesh   10 years AGO

21 should be the ans

Like? Yes (1) | No   

Akshay Kumar Jain   10 years AGO

The ans would be 21 As the in the series the difference is in the series like 3-12 6-3310-6415-105 therefore 21-156

Like? Yes (1) | No   

Bhanu Pratap Singh   10 years AGO

consecutive difference of terms is 2345 so next term will be 15621

Like? Yes (1) | No   

MRSwetha   10 years AGO

it should be 2112333664101051515621

Like? Yes (1) | No   

arpit agarwal   10 years AGO

112333664101051515621

Like? Yes (1) | No   

bhishma   10 years AGO

12333664101051515621

Like? Yes (1) | No   

anudeep   10 years AGO

difference between two numbers is increasing by one

Like? Yes (1) | No   

jhansi   10 years AGO

12333664101051515621

Like? Yes (1) | No   

Deepu Kumar   10 years AGO

AQ Option 10 is correct

Like? Yes (1) | No   

shivakrishna   10 years AGO

1231051515621

Like? Yes (1) | No   

Simranjit Singh   10 years AGO

12 333 664 1010515156 21So None of these

Like? Yes (1) | No   

Ritesh Kumar   10 years AGO

21

Like? Yes (1) | No   

vatan singh   10 years AGO

1361015the difference between no is 2345 ie an AP therefore next nois 6hence next no is 15621ans 21

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RAKESH   10 years AGO

next no. = 15+6 = 21
10) none

Like? Yes (1) | No (2)