Assume Total is 100 Tired Not Tired Total Sleep < 6 3/4 or 75% of 80 = 60 1/4 or 25% of 80 = 20 80 Sleep >= 6 3/10 or 30% of 20 = 6 7/10 or 70% of 20 = 14 20 Total 66 34 100 Guess I am perplexed that 75% of 100 is being used rather than 75% of 80 and 25% 80. Yeah, using the matrix is helpful; ...

One more way. Please let me know if there's a mistake with this. ... You can not assume that the number of upgraded sensors (U in your discussion) is the same for each unit. You need to replace the 30 U with the actual number of upgraded sensors, call that S [the sum of the upgraded sensors over al...

you are not alone... :) A bit late posting here based the original post date(s) of this thread. Anyhow, there are three formulas that can calculate a variation of the Sums: (Even, Odd, All). n = number of terms between 600 and 300 inclusive multiples of 15: 300/15 = 20 + 1 = 21 = n Even: n(n + 1) O...