Question

6, 9, 13, 21, 38, 71, ?

Answer 1

Answer:

Step-by-step explanation:

Ans:129

1) find difference between two continuous no.

2) add odd no. In series

For example..

Difference between 9 and 6 is 3 and first odd no. Is 1 so

9+3=12

12+1=13

Now..for second no. Next odd no. Is 3 so we have to do sum of 3 with 1 i.e. 3+1=4 so

13-9=4 difference

13+4=17+4=11

Remember odd no. Have to add with last adding no.

So.. 9+3=12+1=13. (diff. Bet. 6 nd 9 is 3)

13+4=17+4=21. (diff.bet.13 nd 9 is 4 )(1+3=4)

21+8=29+9=38 ( diff.bet.13 nd 21 is8)(4+5=9)

38+17=55+16=71 (diff.bet.38 nd 21 is 17)(9+7=16)

71+33=104+25=129 (diff.bet.38 nd 71 is 33)(16+9=25)

Answer 2

Given data: 6, 9, 13, 21, 38, 71, ?

To find: Next series

Solution:

• Series is the sequence of number in particular order. The order may be in arithmetic operations.
• The given series is 6, 9, 13, 21, 38, 71. In this case the difference between 6 and 9 is 3, 9 and 13 is 4, 13 and 21 is 8 and so on.
• After finding the difference we need to square the natural number to get the difference of next number.
• The difference between 6 and 9 is 3 then we need square the natural number ( $3+1^2=4$ ).
• Similarly the difference between 9 and 13 is 4. Squaring we get $4+2^2=8$.
• Hence the next number in the series is 129.