Convex mirrors - Sign convention trouble

[Elbobo]

Homework Statement

I solved the problem, but upon further observation, I discovered that what I did didn't make sense.

(these are rounded numbers, which shouldn't make a difference in my question)
do = 13 cm (do is what I solved for in the problem, and according to the online system it was correct)
f = 24 cm
di = 33 cm

(the man is facing a convex mirror with his image behind the mirror)

Homework Equations

1/f = 1/do + 1/di

The Attempt at a Solution

Since this is a convex mirror, f and di should be negative. Yet, it doesn't make sense with those conventions.

1/f = 1/do + 1/di
1/do = 1/f - 1/di
1/do = (1/-24) - (1/-33)
do = -88 cm,

which means the object is behind the mirror and my methodology was inconsistent.



Where is the issue? Is it just an inconsistency with sign conventions by them?

 

[rl.bhat]

In the convex mirror, the image cannot be formed beyond the focal length.

 

[Elbobo]

OH! I finally see what I did wrong. I wasn't thinking and at the moment thought that the hubcap is normally viewed as convex. Now I see...