The time passed between when Michelle began her first lap and finished her final lap is 7 minutes and 35 seconds ⇒ B
Step-by-step explanation:
The given is:
- Michelle ran 4 laps around a track, while taking a break in between each lap
- Each lap consisted of 400 meters
- She ran each lap at an average speed of 5 meters per second and rested for 45 seconds between each lap
We need to find how much time passed between when Michelle began her first lap and finished her final lap
∵ She ran 4 laps
∵ She take a rest between each two laps for 45 seconds
- between the 4 laps there are 3 rests, the first is between the
1st and 2nd laps, the second is between the 2nd and the 3rd
laps and the third is between the 3rd and the 4th laps
∴ The time for rests = 3 × 45 = 135 seconds
∵ Each lap consisted of 400 meters
- Find the distance of the 4 laps by multiplying 4 by 400
∴ The distance of the 4 laps = 4 × 400 = 1600 meters
∵ She ran each lap at an average speed of 5 meters per second
∵ Time = Distance ÷ speed
∴ The time of 4 laps = 1600 ÷ 5 = 320 seconds
- Find the total time passed between began her first lap and
finished her final lap by adding the times of the 4 laps and
the 3 rests
∴ Her total time = 135 + 320 = 455 seconds
∵ 1 minutes = 60 seconds
- Divide the time by 60 to change it to minutes
∵ 455 ÷ 60 = [tex]7\frac{7}{12}[/tex]
∴ Her total time is [tex]7\frac{7}{12}[/tex]
- Change the fraction [tex]\frac{7}{12}[/tex] minute to seconds
by multiply it by 60
∵ [tex]\frac{7}{12}[/tex] × 60 = 35
∴ Her total time is 7 minutes and 35 seconds
The time passed between when Michelle began her first lap and finished her final lap is 7 minutes and 35 seconds
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