Saturday, April 22, 2017

Complete the number-sequence



2 → 6
3 → 12
4 → 20
5 → 30
6 → 42
9 → ?


Can you find a correspondence between these numbers?


It's not mine, so I don't take any credit. I've just seen it in Linkedin and wanted to share with the community.



Answer





90




Reasoning:



f(n) = n * (n+1)
Thus,
2 * 3 = 6,
3 * 4 = 12,
4 * 5 = 20,

5 * 6 = 30,
6 * 7 = 42,
9 * 10 = 90



No comments:

Post a Comment

classical mechanics - Moment of a force about a given axis (Torque) - Scalar or vectorial?

I am studying Statics and saw that: The moment of a force about a given axis (or Torque) is defined by the equation: $M_X = (\vec r \times \...