Solution

156408

First name
Mahnoor
School
Greenacre Public School
Country
Age
10

The answer for this question is 210. I did it by writing down a list of :

Multiples of five,

Triangular numbers,

Multiples of 3 but not 9,

Even, but not multiples of 4.

Therefore, by doing this, I found a common number from all of these, and that's how I got my answer.