Simple Math Questions

For some reason, I'm doubting my own somewhat meager math abilities lately. I would like to hear someone if I'm doing the following 3 things right.

1) I play a computer game that consists of a series of matches. At the end of each match, depending on performance, I'm awarded a certain number of points, and if I lose the match, I receive negative points. Normally, one would state that past performance is no indication of future performance, like the stock market, but in this case, past performance is a pretty good indicator of what will happen in the future. So, my curiosity gets to a certain point of wondering how many games it would take to earn a certain number of points, normally around 800, not that the specific number matters. I feel like I should be able to add up all the points received in previous games, divide by the number of games to get an average of points won per game. Then I can take the 800, divide by the average points per game, and that should give me how many games it will take to reach 800. Correct or not?

2) Similarly, for my business, I'm working on paying off a capital loan. For the purpose of this, I'm ignoring the effects of interest. Every week I make a payment based upon my profit for the week. Again, I want to know how many weeks until the loan is paid off. Again, past performance is a very good indicator of future performance. Thus, I feel that, as the same in #1, I can get an average weekly payment from the past payments. Take the amount owed, and divide by this average, and I should get the number of weeks until payoff. Yes, I know that the interest will take into effect, but because the rate is so low, I am not as worried about this. Further, this is more to give me an idea of how many weeks to go, not an exact number.

3) I was watching an episode of South Park, in which a dark haired husband and dark haired wife had 3 ginger children. When the South Park boys expressed an amazement at such an occurrence, the father stated that both him and his wife carried a recessive ginger gene, and had been told that there was only a 1 in 4 chance of having a ginger child. Then he stated, what are the odds? Meaning, what are the odds he would end up with 3 ginger children. Again, I'm ignoring any realities, and just going with the story. My initial idea was that if there is a 1 in 4 chance of having a ginger child, then that means a 0.25 probability of a ginger child. Since had had 3, that would be 0.25 x 0.25 x 0.25, which means a 0.015625 probability, or a 1 in 64 chance of having 3 ginger children.

Again, I know this stuff is basic, and I shouldn't be having such a hard time with it, but for some reason, my brain has frozen this past week. Thanks!

All of your math seems reasonable to me.

I would be most concerned about the accuracy of estimate #2. Payment is based on profit, profit is calculated from revenue and expenses. Perhaps assuming all these quantities are costant might not be the best model available. I don't know how much money you're talking about or what the ramifications of an improper estimate might be. Just make sure you're conservative and don't overextend.

I think your math is right.


However, in scenario #1, I'd be concerned with the type of game being played. For example, if it's poker, is the game learning how you play and how you bluff? That could mean that the more you play, the worse you'll do. However, unless it's a VERY good (and therefore expensive) game, it's more likely that it's just playing based on its own parameters. Therefore, you could be learning IT'S bluffing patterns, and you could start winning more / faster.

Thanks guys. None of the issues are used seriously. It was more just the idea that in my head, this math should be fairly easy to do. I figured I was doing it right, but something kept gnawing at me that I was doing it wrong.