A work problem: If Elmo, Zoe, and Rocco work together, how fast can they paint a room?

Thank you for mentioning “without slowing down” and “same size room!” Writing (or in this case speaking) GOOD word problems is so important for good math thinking!!!

@howie_hua these type of questions always scared me too when I was young! Wonderful explanation!

Thank you so much, Frank!

That’s the classic (and in my opinion, the best) way to do it. Another way to think about it is that in 1 hour, 1.75 rooms will be painted if they all paint together. But we only want 1 room painted. So 1/1.75 = 4/7

Mental math solution: Per hour painting rates: ¼ room + ½ room + 1 room = average rate of 1 ¾ rooms per hour Rate / # of people 1 ¾ divided by 3 = (60 minutes / 3) + (45 minutes / 3) = 20 + 15 = 35 minutes

I wish I knew that technique when I was studying :D

Egh you didn't indicate the size of the room 🙄 #StMarksBasilica #Veniza #Italy