Easy Points on the board!!!?

Question

solve and please explain how you did it:

2.1 : 10.5 : 5 = 3 : 2 : y

Answer 1

Ok I think the basic idea is you need to find some relation between the three numbers on the left side, then apply that same relation to the right side.

The obvious one I see is that 10.5 / 2.1 = 5, so SECOND / FIRST = THIRD

Now if we look at the right side, we get y = 2/3.

I have no idea if that's what you're looking for though, the notation is very strange to me.