Explanation
Step 1: Understand the problem statement.
Total number of identical prizes (n) = 10 (since there are 10 games and each game awards one identical prize).
Total number of children (r) = 1 birthday boy + 3 friends = 4 children.
Condition: Each child must receive at least one prize.
Step 2: Use the Stars and Bars theorem.
We need to find the number of ways to distribute n=10 identical objects among r=4 distinct individuals such that each individual receives at least 1 object.
According to the Stars and Bars method (for positive integer solutions), the number of ways to distribute n identical items into r distinct groups where each group gets at least one item is given by the formula:
Number of ways=(r−1n−1)
Step 3: Substitute the values into the formula.
Here, n=10 and r=4:
Number of ways=(4−110−1)
Number of ways=(39)
Step 4: Calculate the combination.
(39)=3×2×19×8×7
(39)=6504
(39)=84
Therefore, there are 84 possible ways to distribute the prizes.
Correct Option: B (84)