Here’s the download link, which includes the third act.
— Kate Fisher (@_K8Fisher) February 20, 2014
I dunno, this one made me wish the follow-up showed him just throwing the paint away and starting over. There’s just not enough investment in materials & time to make me think past. Plus if 6 tablespoons was enough paint to do the job then 30 is just a waste of paint far in excess of throwing away 6.
@Don, what if he had used up all the white paint after putting in the 5 scoops of white? Then he’d have to figure out how to do it by just adding more red.
2014 Mar 11. Great extension for Algebra students from Paul in the comments:
I used the task to set up this question in an Algebra class.
The students were very puzzled when their intuition about the solution did not match arithmetic or a demonstration with cubes.
“I have two cans of pink paint variations in the following ratios. Neither is perfect.
Nana’s Pink 5 Reds : 1 White
50/50 Pink 1 Red : 1 White
I think that a perfect pink will be 3 Reds : 1 White
Can I make it by mixing Nana Pink and 50/50 Pink?”
Students expected the solution to be one cup of each. How wonderful the sound of a perplexed group of students when their arithmetic did not match their intuition.
Sense making ensued for many minutes with pictures, cups with cubes and more arithmetic.