Here are a sequence of deductions I saw in a textbook; given that:
x + y = 1 (x and y are probabilities)
here we go...
1) 0.1x + 0.6y = x
0.9x + 0.4y = y
so therefore
2) x = 0.6/0.9 y
x = 2/3 y
so therefore
3) x = 1 - y
x = 2/3 y
so therefore
4) x = 2/5
y = 3/5
My problem is - I can't understand how the author went from 3) to 4). Now don't get me wrong, I can understand it logically; thinking it over in my head;
IF x = 2/3 y
THEN it must be that y = 1.5x
so 4) makes sense because 3/5 = 1.5 * 2/5
However I just can't figure out what he did with the equations from 3) in order to get those numbers (3/5 and 2/5)