To find the height of the ball after 7.5 seconds, we need to evaluate the function \( h(s) = -s^2 + 10s + 3 \) at \( s = 7.5 \).
Let's substitute \( s = 7.5 \) into the function:
\[ h(7.5) = -(7.5)^2 + 10(7.5) + 3 \]
Now, calculate \( (7.5)^2 \):
\[ (7.5)^2 = 56.25 \]
Now, plug it back into the equation:
\[ h(7.5) = -56.25 + 10(7.5) + 3 \]
Calculate \( 10(7.5) \):
\[ 10(7.5) = 75 \]
Now substitute and simplify:
\[ h(7.5) = -56.25 + 75 + 3 \]
Calculating step by step:
- Add \( 75 + 3 = 78 \)
- Then, \( 78 - 56.25 = 21.75 \)
Thus, the height of the ball after 7.5 seconds is:
\[ h(7.5) = 21.75 \]
The correct response is \( 21.75 \).