Science NFT -Need math help

Frosty · 01-22-2009, 03:29 PM

Since it seems to be homework day on CP, I was hoping there were some math wizzes around. In the past, there were a few math majors around, IIRC.

My wife is helping out with the Math Is Cool team at our middle school and has run into a problem that she can't explain how to do mathematically. I am no help here because I sucked at probability in college.

The problem goes something like:"Cindy is buying four balloons. She can pick from any of four different colors. How many unique combinations can she make?"

On first thought, it would just be 4x4x4x4 (256). However, some of those combinations are duplicates (RRBB = RBBR). You can brute force it out by listing the different combinations to get the answer of 35 but this is too slow for a competition.

Any help on how to explain this mathematically so the kids can do the problem quickly?

01-22-2009, 03:29 PM	Topic Starter
Frosty Go Beavers! Join Date: Jan 2001 Location: Washington Casino cash: $3518243	NFT -Need math help Since it seems to be homework day on CP, I was hoping there were some math wizzes around. In the past, there were a few math majors around, IIRC. My wife is helping out with the Math Is Cool team at our middle school and has run into a problem that she can't explain how to do mathematically. I am no help here because I sucked at probability in college. The problem goes something like:"Cindy is buying four balloons. She can pick from any of four different colors. How many unique combinations can she make?" On first thought, it would just be 4x4x4x4 (256). However, some of those combinations are duplicates (RRBB = RBBR). You can brute force it out by listing the different combinations to get the answer of 35 but this is too slow for a competition. Any help on how to explain this mathematically so the kids can do the problem quickly?
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