Assume a healthy heart beats exactly 70 times per minute. If an individual lives to age 85 years, estimate the number of heartbeats in his or her lifetime, using scientific notation.

3.12732 × 10⁹ beats

Step-by-step explanation:

Given that, in 1 min, the heart of an individual makes 70 beats, the number of beats the heart of the healthy individual makes in 85 years can be calculated as follows:

1 yr = 365 days, therefore,

85yrs = 85*365 = 31,025 days

1 day = 24 hours

31,025 days = 31,025*24 = 744,600 hours.

1 hr = 60 mins

744,600 hours = 744,600*60 = 44,676,000 mins

This means the individual lived for 44,676,000 mins (85yrs)

If 70 beats are made in 1 min, therefore, in 85yrs, the individual will make:

44,676,000*70 = 3,127,320,000 beats = 3.12732 × 10⁹ beats in 85yrs