???
Typo.
Okay then, I'll try to explain this in detail.
We have 2 values.
Variable 1: at location 0.3 and value of 0.25
Variable 2: at location 0.8 and value of 0.7
We want to figure out the value Y for Variable 3 at location 0.5.
Since the game is using linear interpolation (not sure if this is the correct term) we are using this as well. The only thing we know about this unknown value is that it is between the values of Var1 and Var2. (Because linear interpolation)
First we need to find out slope
m, we do this by calculating the difference between x (time) and y (value).
m = (0.7 - 0.25) / (0.8 - 0.3)
m = 0.45 / 0.5
m = 0.9
The value goes up 0.9 for every 1.0 unit of time. (Notice! Not every 0.1!) Now we just need the difference between the starting point and the point of time at which we want the value.
0.5 - 0.3 = 0.2
0.2 * 0.9 = 0.18
Now we know that the value goes up by 0.18 units between Var1 and Var3.
0.3 + 0.18 = 0.48
TL;DR
http://www.mathsisfun.com/straight-line-graph-calculate.htmlYou still need to find the unknown value yourself but it's a lot faster since you get the slope right away.
Professor Demian signing off, the class is over.