Chapter 8.3, Problem 27STP

To determine

Find the correct equation from the options given.

Answer to Problem 27STP

Option C is correct.

Explanation of Solution

Given:

A hot air balloon is at an altitude of 113.2 meters. The balloon`s altitude decreases by 10.8 meters every minute. Which equation can you use to find the number of minutes m until the balloon`s altitude is 70 meters?

4 options are:

  $\text{A: 113}\text{.2m }-\text{ 10}\text{.8 = 70 ; B: 113}\text{.2m + 10}\text{.8 = 70; C: 113}\text{.2 }-\text{ 10}\text{.8m = 70 ; D: 113}\text{.2+ 10}\text{.8m = 70 }$

Concept Used:

A hot air balloon is at an altitude of 113.2 meters, it means the initial height is 113.2 meters.

The balloon`s altitude decreases by 10.8 meters every minute, so in m minutes balloon`s altitude decreases by $\text{10}\text{.8m}$ .

Calculation:

Initial altitude is 113.2 meters and in m minutes balloon`s altitude decreases by $\text{10}\text{.8m}$ .

So the required equation is $\text{113}\text{.2 }-\text{ 10}\text{.8m = 70}$

Option C is correct.

Thus, option C is correct.