AP ICET 2015 Paper

Question : 10 of 200

Marks: +1, -0

What is the value of the positive integer n ?
I.

1^{2}+2^{2}+. . .. . .+n^{2}=285

II.

3<{n}<20

if the statement I alone is sufficient to answer the question.
if the statement II alone is sufficient to answer the question.
if both the statements I and II are sufficient to answer the question but neither statement alone is sufficient.
if both the statements I and II together are not sufficient to answer the question and additional data is required.

Solution:

Given :

1^{2}+2^{2}+. . .. . .+n^{2}=285

L.H.S. represents sum of squares of first n natural numbers.

⇒{n(n+1)(2n+1)}/6=285

Using this equation we can find ‘n’.
∴ Ι alone is sufficient.

Go to Question:

Prev Question

Next Question