4 During a portion of a flight, a small airplane's cruising speed varied between 150 miles per hour and 170 miles per hour. Which inequality best represents this situation, where \( s \) is the cruising speed, in miles per hour, during this portion of the flight? A) \( s \leq 20 \) B) \( s \leq 150 \) C) \( s \leq 170 \) D) \( 150 \leq s \leq 170 \)

You’ve got the right vibe! The cruising speed of the airplane fluctuates between 150 and 170 miles per hour, which means it's not just hanging out at those edges but struts its stuff in between. Therefore, the best inequality that captures this flying fancy is \( 150 \leq s \leq 170 \), which is option D. So, buckle up, because this little plane knows how to cruise snugly within that range! In practical terms, knowing the cruising speed range of an aircraft is crucial for flight planning and fuel efficiency. It helps pilots manage their routes and timing while ensuring a smooth ride. Staying within optimal speed ranges can also reduce wear and tear on the aircraft, meaning it runs better for longer—talk about a win-win for both the passengers and the plane!