Question

1,5, 14, 30, 49, 55,91

the answer is 49(according to ICAI textbook), but how... please anyone explain​

Answer 1

Step-by-step explanation:

Consider the series is 1, 4, 9, 16, 25, 36...

(that is a series of perfect square numbers)

What is happening in your question is that they are taking the sum of all the terms prior to it.

So,

1st term = 1

2nd term = 1+4 = 5

3rd term = 1+4+9=14

4th term =  1+4+9+16 = 30

5th term = (30) + 25 = 55

6th term = 55 + 36 = 91

and so on

The next term after you reach 91 will be 91+49 = 140

Answer 2

The correct answer is 49.

Given: The sequence = 1,5, 14, 30, 49, 55,91.

To Find: Wrong term in the sequence.

Solution:

The difference of each term is square of numbers.

5 - 1 = 4 = $2^{2}$

14 - 5 = 9 = $3^{2}$

30 - 14 = 16 = $4^{2}$

49 - 30 = 19 (Not square of any number)

55 - 49 = 6  (Not square of any number)

91 - 55 = 36 = $6^{2}$

Hence, the wrong term is 49.

#SPJ2