Two are produced by a cosmic ray collision at an altitude of 30 km. The two

Two μ are produced by a cosmic ray collision at an altitude of 30 km. The two energies are E₁ = 5 GeV and E₂ = 5 TeV. What are the distances at which each of the muons sees the surface of the Earth in its rest reference frame? What are the distances travelled in the Earth reference frame in a lifetime?