To find out how many flowers Tony has, we can use the total number of flowers and the number that Jack and Jenny have.
Total flowers = 18
Jack's flowers = 5
Jenny's flowers = 10
Now we can calculate the number of flowers Tony has by subtracting the number of flowers Jack and Jenny have from the total:
Tony's flowers = Total flowers - Jack's flowers - Jenny's flowers
Tony's flowers = 18 - 5 - 10
Tony's flowers = 18 - 15
Tony's flowers = 3
So, Tony has 3 flowers.
The answer is 3.