A space probe projected from the earth moves round the moon in a circular orbit at a distance equal to its radius Rₘₒₒₙ= R/4 where R = radius of the earth. Its rocket launcher moves in circular orbit around the earth at a distance equal to R from its surface. The ratio of the times taken for one revolution by the probe and the rocket launcher is (Mₘₒₒₙ = M/80, where M = mass of the earth))