Chapter 1, Problem 55A

Interpretation Introduction

Interpretation : The times that the heart will beat in an hour and a day are to be calculated.

Concept Introduction : The methods for solving numerical problems are arranged into a three-step approach to problem-solving. Analyzing, calculating, and evaluating are the steps in solving a numerical word problem.

Answer to Problem 55A

The heart beats $4320\text{times}$ in an hour and $103680\text{times}$ in a day.

Explanation of Solution

Given information:

The heart beats at a rate of 72 times per minute.

It is known that $\text{1}\text{day}\text{=}\text{24}\text{hr}$ and $\text{1}\text{hr}\text{= 60}\text{mins}$ .

To calculate the heartbeat for 1 hour, follow the calculation below:

  $\begin{array}{c}1\text{hour}\text{=}\text{1}\cancel{\text{hr}}\text{×}\frac{\text{72}\text{times}}{\text{1}\cancel{\text{min}}}\text{×}\frac{\text{60}\cancel{\text{min}}}{\text{1}\cancel{\text{hr}}}\\ =4320\text{times}\end{array}$

To calculate the heartbeat for 1 day, follow the calculation below:

  $\begin{array}{c}1\text{day}\text{=}1\cancel{\text{day}}\text{×}\frac{\text{72}\text{times}}{\text{1}\cancel{\text{min}}}\text{×}\frac{\text{60}\cancel{\text{min}}}{\text{1}\cancel{\text{hr}}}\times \frac{24\cancel{\text{hr}}}{1\cancel{\text{day}}}\\ =103680\text{times}\end{array}$

The heart beats $4320\text{times}$ in an hour and $103680\text{times}$ in a day.