Answer:
[tex]a''_b=18\ m[/tex]
Explanation:
Given:
By the laws of reflection we know that the image of an object appears at the same distance from the surface of a plane mirror as that of the object from the surface of the mirror.
Now the distance of the head from the rear mirror:
[tex]b=7-2.5[/tex]
[tex]b=4.5\ m[/tex]
Now the distance of image of the back of head in the rear mirror from the object head:
[tex]b'=2\times 4.5[/tex]
[tex]b'=9\ m[/tex]
Now this image is reflected into the front mirror from the image of the back of the heat in the rear mirror.
So, this is the second reflection of the actual object, which will form at a distance of:
[tex]a''_b=2\times 9[/tex]
[tex]a''_b=18\ m[/tex]