Problem of the Week

Submitted by Brooke Istas on Thu, 11/07/2013 - 17:48
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Hello All!

As a community of practice, I am sure that several of you struggle to find engaging, fun, and high-quality math material.  Therefore, I will be posting a problem each week that we can discuss and that you may then use in your classrooms.  Please feel free to also post any feedback you receive from your learners or any interesting classroom outcomes.  Here is this week's problem:

Using simple interest answer the following question and explain your results.

Kay has $10,000 to invest. She invests $4,000 at 5 percent and $3,500 at 4 percent. To have a yearly income of $500 from the investment, at what rate must she invest the remainder of the money?
 
 
Let's have fun!
Brooke Istas, SME
Math and Numeracy
 

 

Comments

The more material I peruse concerning the new tests, the more I see "four-or-more-steps" in a problem. I haven't seen it written out in black-and-white but I surmise that the rigor shift of the CCRS is at the heart of this move. I feel that problems like this, where a formula is needed-as well as several small steps- is a great preparation tool for students taking the test next year. I will try this with my students next week.   

I plan on using your problem each Monday and having my students work on their own or in groups. At the end of the week, we will do the activity together. I may even have a little competion as to who can come up with the answer first. Anyway, thanks, Brooke! I look forward to a new problem each week!

  I like your idea for presenting a weekly math problem for discussion within the community.  I have a suggestion.  I was wondering if you might consider listing the standards from the College and Career Readiness Standards for Adult Education that are included in solving the math problem?   Meryl Becker-PrezockiCollege and Career Standards SME

I posted the math problem for my Tuesday and Wednesday math students.  Most solved the problem the same way I would by first calculating the amount Kay makes from her two investments and subtracting that total from the $500 she desires.  She is left with wanting to make $160 more.  Then they subtracted the total amount invested from the initial $10,000.  One student completely missed the $10,000 start figure and solved for a different question.  At this point, it was interesting to see students approached it from different ways of thinking.  Most realized they needed to divide the $160 by $2500 to arrive at 6.4% for a rate.  However, one student broke down the division in his head and used 1/25 to arrive at .04, then 6/250 to arrive at .024 and added them together to get .064 or 6.4%.   I was especially please to have a basic skills student attempt the problem and get most of the way through it!  They are looking forward to the next one :)

I use the last 7-10 minutes of each class with a problem - usually a non-traditional problem.  I used this problem with great success.  Because of the real world application, the students followed the problem.  I would say the biggest obstacle was organizing all the information, but once the numbers were organized, the students followed the process.