Answer:
 LeBron trimmed for 1 hour and mowed for 2 hours
Explanation:
Let t represent the number hours LeBron trimmed. Let m represent the number of hours LeBron mowed. The problem statement tells us two relationships:
 m = 2t . . . . . LeBron spent twice as many hours mowing as trimming
 (5.50 +5.00m) + (3.50 +6.50t) = 25.50
Substituting for m and collecting terms, we have
 9.00 + 16.50t = 25.50
 16.50t = 16.50
 t = 1
 m = 2·1 = 2
LeBron spent 1 hour trimming and 2 hours mowing.