Answer:
375 tickets
Explanation:
1. Add 15%, 50%, and 10% together to get 75%.
2. Subtract 75% from 100% to get 25%.
3. Multiply 1,500 by 0.25 (the decimal equivalent to 25%) to get 375.
4. You can also do it individually by multiplying 15% by 1,500 then 10% by 1,500 and 50% by 1,500 and adding them together and then subtracting it by 1,500. However, this would take much more work.