Question

If we add the first n odd numbers we get ______

(a) n^2

(b) 2n

(c) 3n

(d) n

The question was posed to me in a job interview.

My enquiry is from Properties of Squares in portion Squares and Square Roots of Mathematics – Class 8

Answer 1

Correct choice is (a) n^2

To explain: When we add first n odd numbers we get, n^2.

For example: the first 5 odd numbers are 1, 3, 5, 7 and 9

When we add them, we get, 1+3+5+7+9+=25. We know that 25 is the square of number 5. Hence, we find that when first n numbers are added we get n^2.