Ravi drove for 4 hours at a speed of 70 miles per hour and for 2 hours at 40 miles per hour. What was his average speed (in miles per hour) for the whole journey?
Explanation:
Total distance travelled by Ravi = 4 × 70 + 2 × 40 = 360 miles
Total time taken by Ravi = 4 + 2 = 6 hours.
∴ Average speed of Ravi = 360/6 = 60 miles/hour.
Hence, option (b).