Question

Assume a healthy hearts beats exactly 70 times per minute. If individual lives to age 85 years, estimate the number of heartbeats in their lifespan using scientific notation and the correct number of sig figs.

Answer 1

Given :

Number of heart beat in 1 minute , n = 70 .

The individual lives for 85 years .

To Find :

The number of heartbeats in their lifespan .

Solution :

Now , number of minutes in one hour is 60 .

One day contains 24 hours .

Therefore , minutes in one whole day :

`24* 60 = 1440\ sec`

Now , 1 year contains 365 days .

( Note : We are not considering any leap years )

Minutes in one year are :

`365* 1440=525600=5.25* 10^5\ sec`

So ,total minutes in 85 years is :

`=5.25* 10^5* 85\\\\=4.46* 10^7\ sec`

Hence , this is the required solution .