Answer:
20th, 40th, 60th day.
Step-by-step explanation:
From the question given above,
Leon goes to the park every 5 days.
Joe goes to the park ever 4 days.
Since we are trying to obtain the first 3 days in which Leon and Joe will be at the park at the same time, let us obtain a 2 months time table for them knowing that they will be at the park at the same time at least ones in a month.
For Leon:
5th, 10th, 15th, (20th), 25th, 30th, 35th, (40th), 45th, 50th, 55th, (60th).
For Joe:
4th, 8th, 12th, 16th, (20th), 24th, 28th, 32th, 36th, (40th), 44th, 48th, 52th, 56th, (60th).
From the above, Leon and Joe will be at the park same time on the 20th, 40th and 60th day.
