You rode your bicycle to the park and saw a number of other people there. Some were riding bicycles and some were riding tricycles. In total, you saw 51 wheels. 1. How many bicycles and how many tricycles were in the park? 2. What possible combinations of bicycles and tricycles in the park? 3. Explain why the number of bicycles in the park could not be equal to the number of tricycles. Would you please explain it in words?