Images from Two Parallel Mirrors problem

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The problem involves two parallel mirrors located at x = +11.00 m and x = -11.00 m, with a point light source at x = +2.70 m. To find the coordinates of the four images generated by the reflections, one should first identify the reflections of the point source in each mirror. The first image (I1) is the reflection in mirror 1, and the second image (I2) is the reflection in mirror 2. Subsequent images (I12 and I21) are derived from the reflections of I1 and I2 in the opposite mirrors. This method allows for determining the coordinates of all four images based on their distances from the mirrors.
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Homework Statement

Two parallel mirrors that face each other are placed along and perpendicular to the x-axis at x = +11.00 m and x = -11.00 m. Assume that a point source of light is placed on the axis at x = +2.70 m. In principle, there will be an infinite number of images generated. Consider the locations of the four images of the point source with the smallest absolute values of image distance i. Going from left to right (i.e from negative to positive), what is the x-coordinate of the left most image?

2. What is the x-coordinate of the next image?

3. What is the x-coordinate of the next image?

4. What is the x-coordinate of the right most image?


I really do not know where to start, so any help appreciated
 
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Draw a sketch... first draw the reflections of the point source in the two mirrors... what are the coordinates of these two images. I'll call the I1 (reflection in mirror 1) and I2 (reflection in mirror 2). Now I1 and I2 also have reflections... I1 has a reflection in mirror 2... call it I12. you can get the coordinates of this image because you have the coordinates of I1, and therefore you know its distance from mirror 2... so I12 is located on the other side of mirror 2 at the same distance.

And I2 has a reflection in mirror 1... call it I21. You can get I21's coordinates in a similar manner as you got I12's coordinates.

that's 4 images... I1, I2, I12 and I21.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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