PHYSICS ----- LENSES ---- 1 QUESTION ---- I'm not sure if I got it right?

A certain lens focuses an object 2.25 m away as an image 48.3 cm on the other side of the lens. What type of lens is it and what is its focal length? Is the image real or virtual?

----> So here's how I tried approaching it:

First, I drew a diagram of a Double Convex Lens (I think that it's the type of lens described here), and I don't know about the focal length, but the focus point is f = (1/2)*r so, r = 2.25 + 0.483 = 2.733 and f = (1/2) * 2.733 = 1.3665.

And I think that the image is real since that type of lens will keeps the image the same size no matter from which side you look from.

What do you think?

Thanks!
The 1/f = 1/0.483 - 1/(-2.25) should be 1/f = 1/0.483 + 1/(2.25)

I got it now, thank you!