Current Attempt in Progress

Problem A small mirror is attached to a vertical wall, and it hangs a distance of $1\mathrm{.}55$ m above the floor. The mirror is facing due east, and a ray of sunlight strikes the mirror early in the morning and then again later in the morning. The incident and reflected rays lie in a plane that is perpendicular to both the wall and the floor. Early in the morning, the reflected ray strikes the floor at a distance of $3\mathrm{.}01$ m from the base of the wall. Later on in the morning, the ray is observed to strike the floor at a distance of $1\mathrm{.}17$ m from the wall. The earth rotates at a rate of $15\mathrm{.}0$ per hour. How much time $($in hours$)$ has elapsed between the two observations?