Final answer:
The percent of experienced players on the soccer team after the coach adds x experienced players can be calculated using the expression 100(x/4)/(x + 10).
Step-by-step explanation:
The expression is given as: 100(x/4)/(x + 10).
To find the percent of experienced players on the team after the coach adds x experienced players, we need to substitute the value of x into the expression and simplify.
For example, if the coach adds 5 experienced players, the expression becomes: 100(5/4)/(5 + 10).
To find the final percent, we simplify the expression: 100(5/4)/(5 + 10) = 25/3 ≈ 8.33%.