Chapter 11.6, Problem 69PPS

(a)

To determine

To find: The total time that marina spent on riding the bike on two days.

Answer to Problem 69PPS

Here, the total time spent on riding her bike on two days is $\frac{7+2x}{5}$ .

Explanation of Solution

Given:

Average rate of riding the bike is10miles per hour

First day, she rides 9 miles

Second day, she rides 5 miles

Calculation:

The objective is to write an expression to represent the total time spent on riding her bike on two days.

For the day $1$ , the expression is as follows.

  $t=\frac{9+x}{10}$

For the day $2$ , the expression is as follows.

  $t=\frac{5+3x}{10}$

So, the total time spent for two days is calculated below.

  $\frac{9+x}{10}+\frac{5+3x}{10}$

  $=\frac{9+x+5+3x}{10}$

  $=\frac{14+4x}{10}$

  $=\frac{7+2x}{5}$

Conclusion:

Therefore, the total time spent on riding her bike on two days is $\frac{7+2x}{5}$ .

(b)

To determine

To find: the total time taken to ride the loop.

Answer to Problem 69PPS

Here, the total time taken to ride the loop is $\frac{11}{5}$ or $2.2$ hour.

Explanation of Solution

Given:

The loop is $2$ miles long.

Calculation:

The objective is to find the time taken to ride the loop.

The total time is calculated below.

  $\frac{7+2x}{5}$

  $=\frac{7+2\left(2\right)}{5}$

  $=\frac{7+4}{5}$

  $=\frac{11}{5}$ or $2.2$

Conclusion:

Therefore, the total time taken to ride the loop is $\frac{11}{5}$ or $2.2$ hour.