Equation Needed to Find Probability Based on 2 10-Digit Numbers

[jvderosa94]

I'm trying to find an equation to calculate a probability based on 2 ten digit numbers. I'm terrible at math and don't really know how to word it, so I created an excel spreadsheet showing the relationship between the two numbers. It's very linear and should be very easy to do (I would imagine).


The equation should take two numbers, a and b (letters aren't important) and should output the percentage.

 

[ksdhart2]

Reading down the first column shows that the percentage decreases by 5 points for each one unit we increment $b$ by. Likewise, reading across the first row shows that the percentage decreases by 5 points for each unit we increment $a$ by. Based on this, what can you say about how much the percentage would decrease if you incremented both $a$ and $b$ by one unit each? What would happen to the percentage if you incremented $a$ by 5 units and $b$ by 3 units? What would happen if you increased $a$ by 7 units and $b$ by 8 units? Where does all of this lead you?

 

[Harry_the_cat]

You say: "I'm trying to find an equation to calculate a probability based on 2 ten digit numbers."

Do you mean 2 digit numbers?

Also should the row and column headed "10" really be "0"?