In a land of dwarfs, a mysterious dwarf decides to visit three of her friends. She carries 7 mangoes in her sack. To reach her first friend, she crosses a magic river. After she crosses the river, the number of mangoes in her sack doubles. She then gives her first friend a number of mangoes. She continues her journey and then crosses the second magic river, the number doubles again. She crosses the third magic river. Again the number of mangoes doubles. She visits her third friend and gives the same number again. This there are no mangoes left. What number did she give to each friend.​