Convergent lenses and calculating image position

[mortymoose]

Homework Statement

Two convergent lens are identical in focal length (f=10cm) and the oobject height (h0) is 3.5 cm. The distance between the two lenses is 30cm and the distance from the object to the first lens is 30cm.
-Draw a diagram on the figure and show the image position (di) and size (hi) formed by the two lenses.

Homework Equations

1/f = 1/s' +1/s
h'/h = - s'/s

The Attempt at a Solution

The first place I think I am getting confused is whether or not two images are formed. When I did my work that is what i assumed.
My first step was to solve for the first image location:
1/10 = 1/30 +1/s'
s' =15cm
so, first imag eis 15cm in front of first lens
then the height of the first image:
h'/3.5cm = -15/30
h'= -1.75cm

Second image location:
1/10=1/25 +1/s'
s'= 16.6cm
the second image is 16.6cm in front of the second lens
height of second image was:
h'/-1.75cm = -16.6cm/15cm
h'= 1.9cm
So this image would be real, inverted, and reduced in size

But then I am supposed to use 1/d0 + 1/di =1/f
and that's where i realized i must be doing something wrong, because I assumed that two images would be formed but they are only asking for the one image

 

[BvU]

Second image location:
1/10=1/25 +1/s'

Check if this matches your actual problem statement. From your post #1, I conclude 15 cm, not 25.

Can you post the picture ?

 

[rude man]

There is a real image formed by the lens closer to the object, then that image becomes the object for the other lens.
I believe they want you to determine the height and location of the image produced by the other lens.