Ellen is baking bread. It takes 3 hours to rise 1 ball of dough, and then another 2 hours to bake it. If she makes 4 balls of dough one after another and then bakes them one after another when they're done rising, how many hours will it take? Let's answer step by step:
Ellen takes 4 * 3 = 12 hours in total to rise all balls of dough. It will take 4 * 2 = 8 more hours to bake each one. It will take her 12 + 8 = 20 hours to make all of the bread. The answer: 20.