# If, for a positive integer n, the quadratic equation,

Question:

If, for a positive integer n, the quadratic equation, $x(x+1)+(x+1)(x+2)+\ldots .+(x+n-1)(x+n)=10 n$ has two consecutive integral solutions, then $\mathrm{n}$ is equal to :

1. 11

2. 12

3. 9

4. 10

Correct Option: 1

Solution: