To calculate Jack's average speed for the whole jog, you need to find the total time he spent jogging and then divide it by the total distance he covered. Here's how to do it:
1. Jack took 20 minutes to jog around the race course the first time, which is 3 miles.
2. He took 25 minutes to jog around the race course the second time, which is also 3 miles.
Now, calculate the total time Jack spent jogging:
Total Time = Time for the First Lap + Time for the Second Lap
Total Time = 20 minutes + 25 minutes
Total Time = 45 minutes
3. Convert the total time from minutes to hours (since there are 60 minutes in an hour):
Total Time (in hours) = 45 minutes / 60 minutes/hour
Total Time (in hours) = 0.75 hours
4. Calculate Jack's average speed:
Average Speed (in miles per hour) = Total Distance / Total Time
Average Speed = (3 miles + 3 miles) / 0.75 hours
Average Speed = 6 miles / 0.75 hours
Average Speed = 8 miles per hour
So, Jack's average speed for the whole jog is 8 miles per hour.
The correct answer is (B) 8.