Jerry is 8 years younger than Patricia, so:
(1): Jerry = Patricia - 8
Six years ago, Patricia was 3 times as old as Jerry was then, so:
(2): (Patricia - 6) = (Jerry - 6)*3
Putting equation 1 in to equation 2
(Patricia - 6) = (Patricia - 8 - 6)*3
Patricia - 6 = 3Patricia - 42
36 = 2Patricia
Patricia = 18
And so Jerry = 10