Final answer:
The expression to show how many hours Kyle practices is 2.5t, where t equals the number of hours Grant practices.
Step-by-step explanation:
If Kyle practices 2.5 times as many hours as Grant does, and we let t represent the number of hours Grant practices, then the expression to show how many hours Kyle practices would simply be 2.5t. This is because we are given the ratio of Kyle's practice time to Grant's practice time, which we can use to express Kyle's practice time in terms of Grant's.