To find the distance the car travels in the fifth second, we can use the given formula for the distance traveled in the \( n \)-th second:
\[ d_n = 50n - 20 \]
Now, we need to find \( d_5 \) (the distance traveled in the fifth second):
\[ d_5 = 50(5) - 20 \]
Calculating this step-by-step:
- Calculate \( 50(5) = 250 \)
- Then subtract 20: \( 250 - 20 = 230 \)
So, the distance the car travels in the fifth second is:
\[ d_5 = 230 \text{ ft} \]
Thus, the correct answer is:
D. 230 ft