Final answer:
The time taken to cover the distance of 280 miles at a speed of 70 miles/hour is correctly calculated as 4 hours, using the formula time = distance ÷ speed.
Step-by-step explanation:
The question asks us to find the correct time taken to cover a distance of 280 miles at a speed of 70 miles/hour.
To calculate this, we can use the formula time = distance ÷ speed.
Therefore, the correct time taken is 280 miles ÷ 70 miles/hour = 4 hours.
Therefore, option 4 is the correct answer as it corresponds with our calculation.