Improbable Vest-Making
Question from the most recent Math 015 exam: "It takes 3 1/4 hours to make a single beaded vest. There are 52 working hours. How many vests can be made in this time?"
Correct answer is to divide 52 by 3 1/4 --> 52/(13/4) = 52*(4/13) = 16 vests.
Many got this answer or something close to it. Several came up with 169 vests (by multiplying rather than dividing). One person came up with a number over 700. Let's see, it takes more than 3 hours to make a vest, and you're going to make 700 of them in 52 hours? I'd like to see your time machine!
Queue:
math
12 comments:
Shouldn't it be obvious that if they take more than an hour to make, the answer has to be less than 52?
One would THINK so... I'm going to point this out to them tomorrow.
In their defense, fractions confuse the dickens out of them. If I'd said "52 hours" and it takes "4 hours per vest" I'll bet most of them would have divided.
"The student who brings down that balloon doesn't have to learn fraction!"
Maybe the student who answered 700+ actually has super-speed-powers and took that into account while doing the problem.
I went through that with a lot of 108 students, trying to convince them that fractions are numbers too.
Fractions are numbers?
*snickers*
Yes, and they deserve equal numerical treatment, not anti-fraction discrimination!
*the square root of seven quietly cries in the corner*
Lobbyists.
Uh oh...it'll be crying endlessly without ever repeating itself. But at least it keeps getting quieter.
But it's got LOTS of friends: one between every fraction!
That's okay; we need the moisture.
Numbers don't intimidate me.
Post a Comment