Question

A telephone company charges $0.75 for the first 10 minutes of a call and $0.15 for each additional minute. Which interval below represents how a person can talk for $25 (assume that a person cannot talk for a fraction of a minute)?

Option 1: 0 ≤ s ≤ 167
Option 2: 0 ≤ s ≤ 132
Option 3: 0 ≤ s ≤ 145
Option 4: 0 ≤ s ≤ 171

Answer 1

To find the interval of how long a person can talk for $25, set up an equation to represent the cost and solve for the maximum number of minutes. The interval is represented by 0 ≤ s ≤ 171.

Step-by-step explanation:

To find the interval of how long a person can talk for $25, we need to determine the maximum number of minutes that can be afforded with this budget. The telephone company charges $0.75 for the first 10 minutes and $0.15 for each additional minute. Let's set up an equation to represent this:

Total cost = $0.75 + $0.15n, where n is the number of additional minutes.

To find the maximum number of minutes, we need to set the total cost equal to $25 and solve for n:

$25 = $0.75 + $0.15n

Subtracting $0.75 from both sides, we get:

$24.25 = $0.15n

Dividing both sides by $0.15, we get:

n = 161.67

Since a person cannot talk for a fraction of a minute, the maximum number of additional minutes that can be afforded with $25 is 161. Therefore, the interval is represented by 0 ≤ s ≤ 171 (including the first 10 minutes).