Photo (4)

 

Did this kid just get excited by a coincidence? Or is there something deeper going on here?

(Thanks Tina!)

  • My first reaction to this is focused more on the question structure rather than the answer structure. This makes me think about how careful we have to be at times about what numbers we use. I don’t think that I would have realized this tripling business was unfolding with the first three parts of the question.

    • The “tripling business” is the mistake… The function shouldn’t be exponential or tripling. Part b just happened to be 3x Part a.

      • Well, and part c is triple part b. More generally, if the inputs to this function are (p, 1/2, 1-p), then the outputs form a geometric progression.

        An observant student!

        • (Of course, that’s (p, 1/2, 1-p) as fractions, so (x, 50, 100-x) as percentages.)