Let "n" be the number of the 2-hour mysteries. Then the number of the Space Adventures movies is 2n. The total time spent equation is 2n + 1.5*(2n) = 15 hours. 2n + 3n = 15 5n = 15 ====> n = 15/5 = 3. Answer. Three 2-hours mysteries and six 1.5-hours space movies. 6*1.5 = 9 hours was spent for space movies.