Math Problem of the Week

Some students expressed an interest in having a math problem of the week. I will try to provide an interesting problem each week. Remind me if I forget. See if you can be the first to correctly solve the problem. I will post the weekly winners.

You can submit your solutions to me through Edmodo. Please attach your work to your Edmodo message to me. If you are a student that does not have an Edmodo account with me, send me an email at krstitt@gmail.com.

Have fun.

PoW for October 18, 2010

Solve for x:

4(8^x)-21(4^x)+21(2^x)=4

PoW for October 25, 2010

A boy has six yellow marbles and four blue marbles, each distinct from the others. He arranges his ten marbles in a row. What is the probability that no blue marble lies next to another?