How Do You Calculate Object-Image Separation for a Convex Mirror?

[olyviab]

Homework Statement

A convex spherical mirror has a radius of curvature R = 20.0 cm and produces an
upright image precisely one-quarter the size of an object. Calculate the
separation distance between the object and its image?

Homework Equations

M = (image height)/(object height) = h'/h = -q/p

1/q + 1/p = 1/f

q = length from mirror to image
p = length from mirroe to object
f = focal point

The Attempt at a Solution

FOR FINDING p (length from mirror to object)

h = 4h'

h'/h = -q/p

h'/4h' = -q/p

q = -p/4

1/(-q) = 1/f - 1/p

4/p + 1/p = 1/f

5/P = 1/10

P = 50

I know this cannot be right because when i go to calculate q it is greater than the focal point and that does not work.
Any help would be great.

 

[rl.bhat]

4/p + 1/p = 1/f
This substitution is not correct.
Use proper sign conversion for image distance, object distance and the focal length.