Chapter 8.1, Problem 64HP

To determine

How many times can she walk around the track in a half hour.

Answer to Problem 64HP

  $\text{Eight and a half times}$

Explanation of Solution

Given information:

She can walk around the gym track twice in 7 minutes.

Concept Used:

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similar sign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

Calculation:

In order to find the number of rounds that she can walk around the track in a half hour, use the unitary method with the given information as shown below,

  $\begin{array}{c}\text{In 7 minutes she can walk}=2\text{ rounds}\\ \text{In 1 minutes she can walk}=\frac{2}{7}\text{ round}\\ \text{So in 30 minutes she will walk}=\frac{2}{7}\times \text{30 rounds}\\ \text{=}\frac{60}{7}\text{ rounds}\\ \text{=8}\text{.57 rounds}\end{array}$

Thus, in a half hour she can walk around the gym track 8 and half times.