# scientific notation- do i have it correct?

The human heart beats approximately 70 times per minute. Express in scientific notation. how many times the heart beats over a lifetime of 80 years.

I put 2.94 X 10^9 is this correct?

### 4 Answers

- KrishnamurthyLv 74 weeks agoFavorite Answer
The human heart beats approximately 70 times per minute.

How many times the heart beats over a lifetime of 80 years.

Express in scientific notation.

2.94 × 10^9 is correct.

Congratulations!

- busterwasmycatLv 74 weeks ago
I get 2.95x10^9 myself, (2.945376x10^9, actually). I assumed 365.25 days per year rather than a more precise value, though.

- DavidLv 74 weeks ago
In scientific notation 70*80*365.25*24*60 = 2.945376^9 beats over 80 years.

Remember there are actually 365.25 days in a year and that's why we have leap years.

- 4 weeks ago
70 beats/minute * 60 minutes/hour * 24 hours/day * 365.25 days/year * 80 years/lifetime =>

70 * 60 * 24 * 365.25 * 80 beats/lifetime =>

2,945,376,000

They gave you 2 significant figures to deal with, so 2.9 * 10^9 might be the answer they want. But at least you showed an understanding of the method, which is 90% of the battle