Final answer:
To calculate the number of heart beats over 4 years, multiply the average heart rate by the total number of minutes in 4 years. Since the heart rate has only two significant figures, the answers will be reported with the same precision regardless of whether it's 4.0, 4.00, or 4.000 years; the result is approximately 142.1 million beats.
Step-by-step explanation:
Calculating Heart Beats Over Time
To calculate the number of heart beats in a given period of time, you would multiply the average heart rate by the number of minutes in that time frame. Since a typical person has an average heart rate of 73.0 beats/min, we must determine how many minutes are in 4 years. Here are the steps to find the answer:
- Establish the length of a year in minutes (1 year = 365 days, and one day has 1440 minutes).
- Multiply the number of minutes in a year by 4 to get the total number of minutes in 4 years.
- Multiply the total number of minutes by the heart rate (73 beats/min).
However, the question asks for the calculations to be made for 4.0, 4.00, and 4.000 years. The difference here is one of significant figures; 4.0 years has two significant figures, 4.00 has three, and 4.000 has four. The heart rate, though, has only two significant figures, so our final answers for the number of beats will be reported with two significant figures.
- For 4.0 years: 142.1 million beats
- For 4.00 years: 142.1 million beats
- For 4.000 years: 142.1 million beats
The answers remain the same for different numbers of decimal places because the limiting factor is the two significant figures in the heart rate.