Question

A typical person has an average heart rate of 73.0 beats/min. Calculate the given questions. How many beats does she have in 7.0 years? How many beats in 7.00 years? And finally, how many beats in 7.000 years? Pay close attention to significant figures in this question.

Answer 1

The significant figures/digits of multiplication of two numbers is equal to the significant figures of that number which has the smallest significant figures.

eq 1)

but since the lowest number of significant figures is 2 ( in 7.0)  we should round it off as 3700000

hence Number of heart beats= .......the lowest number of significant digit for this product is also 2

Now for 7.00 years we should approximate value from eq 1) as 3680000min

hence number of heart beats = .............3 significant digits in each number

Now for 7.000 years we should approximate value from eq 1) as 3679000min

hence number of heart beats = .............Althogh first number has 4 significant digits, the second has only 3