Question

Find the missing term(s) in the following series. 1, 7, 23, 55, ?, 191

Answer 1

Answer:

a = 1

d = 7 - 1 = 6

So, we need to find 5th term of sequence:

==> 5th  term = a +4d

                      = 1 + 4 X 6

                      = 1 + 24 = 25.

Step-by-step explanation:

Hope it helps :)

Answer 2

Answer:

• missing term will be 109

Step-by-step explanation:

We are given with the series :

1 , 7 , 23 , 55 , ? , 191

Let, the missing term be x

then,

By examining the given series we can conclude that

• 1 = ( 1 )³ - ( 0 )²

• 7 = ( 2 )³ - ( 1 )²

• 23 = ( 3 )³ - ( 2 )²

• 55 = ( 4 )³ - ( 3 )²

by the following pattern

• x = ( 5 )³ - ( 4 )²

and

• 191 = ( 6 )³ - ( 5 )²

therefore,

→  x = ( 5 )³ - ( 4 )²

→  x = 125 - 16

→ x = 109   ( Ans.)

A general formula for finding any term of this sequence :

By examining the pattern of sequence

⇢ nth term of sequence = ( n )³ - ( n - 1 )².