Well, lets think about this. We need to ask our self how many seconds are in one minute. There are 60 seconds in 1 minute. We know he did 4 laps in 5 minutes and 40 seconds. You can change the minutes to seconds by multiplying 60 * 5 = 300 seconds. So 5 minutes = 300 seconds. Now just take the 40 seconds and add it to the 300 seconds, which will give you 340 seconds. So John ran 4 laps in 340 seconds. B wants to know how many seconds it took John per lap...We can find this by dividing 340 by 4 340/4 = 85.
A) 340 seconds
B) 85 sec/lap