To find the height of the ball at 7.5 seconds, we need to evaluate the function \( h(s) = -s^2 + 10s + 3 \) at \( s = 7.5 \).
Substituting \( s = 7.5 \):
\[ h(7.5) = -(7.5)^2 + 10(7.5) + 3 \]
Calculating \( (7.5)^2 \):
\[ (7.5)^2 = 56.25 \]
Now, substituting this value into the equation:
\[ h(7.5) = -56.25 + 10 \times 7.5 + 3 \]
Calculating \( 10 \times 7.5 \):
\[ 10 \times 7.5 = 75 \]
Now, substituting this value into the equation:
\[ h(7.5) = -56.25 + 75 + 3 \]
Combining these:
\[ h(7.5) = -56.25 + 75 + 3 = 18.75 \]
Thus, the height of the ball at 7.5 seconds is \( 18.75 \).
None of the provided responses match this calculation of \( h(7.5) \). Please check the options or ensure that the function is provided accurately.