A survey of Android Apps bought in the App store, indicated that 50% were related to music, 30% related to games, and 20% related to movies

Statistics Nov 18, 2020

A survey of Android Apps bought in the App store, indicated that 50% were related to music, 30% related to games, and 20% related to movies. Twenty percent of the music apps, 40% of the game apps, and 10% of the movie apps are free. What is the proportion of free apps available in the App store?