If both Cody and Lisa play for t hours, then Cody pays a total of $(7 + t), while Lisa pays a total of $(1 + 3t). If they both pay the same amount P, then
7 + t = P
1 + 3t = P
Solve for t :
7 + t = 1 + 3t
t - 3t = 1 - 7
-2t = -6
t = 3
So Cody and Lisa each bowled for 3 hours, and they both ended up paying P = $10.
