Question

A typical person has an average heart rate of 68.0 beats/min. Calculate the given questions. How many beats does she have in 4.0 years? How many beats in 4.00 years? And finally, how many beats in 4.000 years? Pay close attention to significant figures in this question.

4.0 years:_____beats

4.00 years:_____beats

4.000 years:_____beats

Answer 1

Given

heart rate of 68.0 beats/min

We know that

1 year ==> 365 days

4 years ==> 4 years * 365 days/1 year

= 1460 days

1 day = 24 hrs

1460 days ==> 1460 days * 24 hrs/day

= 35040 hrs

1 hr = 60 min

35040 hrs ==> 35040 hrs*60 min/ 1 hr

= 2102400 mins

Given that

For 1 min 68.0 beats

Hence for 2102400 mins ==> 2102400 mins * 68 beats/min

= 142963200 beats

According to the significant rules answer should consist of the number which has least number of significant figures

Here it is 2 significant figures as 4.0 has 2 significant figures

Answer should be 1.4 * 10⁸ beats for 4.0 years

In the second case

The significant figures should be 3 as both 4.00 and 68.0 has 3 significant figures which are least

Answer should be 1.43 * 10⁸ beats for 4.00 years

In the third case

The significant figures should be 3 as 68.0 has 3 which is the least considering 4.000 which has 4 significant figures so the answer should contain 3 significant figures

Answer should be 1.43 * 10⁸ beats for 4.000 years