The natural numbers are divided into groups as (1), (2, 3, 4), (5, 6, 7, 8, 9), &hellip; and so on. Then, the&nbsp;sum of the numbers in the 15th group is equal to&nbsp;

CAT 2021 Question Paper | CAT Verbal Ability Slot 1

Question :

The natural numbers are divided into groups as (1), (2, 3, 4), (5, 6, 7, 8, 9), … and so on. Then, the sum of the numbers in the 15th group is equal to

Started 3 months ago by Shashank in

0 104

A.
4941
B.
6090
C.
6119
D.
7471

Option C is the correct answer.

Explanatory Answer

The natural numbers are divided into groups as (1), (2, 3, 4), (5, 6, 7, 8, 9), ….. and so on.
If you observe that the first group ends with 1², the second group ends with 2²and the third group ends with 3²
Hence, the 15th group ends with 15² = 225.
The 14th group ends with 14² = 196.
Therefore, the 15th group contains (197, 198, . . . . . . . . . . ,225)