[UPSC CSE 1998] Special Theory of Relativity (Q400, 20M)

A \mu meson travels towards the earth's surface from high up in atmosphere with a speed of 0.99\text{ C}. It decays after travelling a distance of 6\text{ km}. In what time does the \mu meson decay as measured by observers in reference frames (i) bound to the earth and (ii) bound to the meson itself.