Question

1. at&t offers different plans for phone data usage. the plan jenna chose has a monthly fee of $25.00, with an additional cost of $15 for each gigabyte of data over. if jenna’s monthly bill was $70.00 in march, how many gigabytes did she go over that month?

equation:
solution:

1. sara needs to rent a car. suppose company x charges a rate of $50 per day and company y charges a $30 fee plus $30 per day. for what number of days is the cost the same?

equation:
solution:

1. an accountant charges $150 per month for bookkeeping services. the accountant also charges $50 per hour for any additional work done. how many hours does the accountant have to work in 1 month to earn $650?

equation:
solution:

1. the length of a rectangle is 5 cm less than three times the width. the perimeter is 76 cm. find the length and the width.

equation:
solution:

Explanation:

Problem 13

Step1: Define variable and equation

Let \( x \) be gigabytes over. Total bill = monthly fee + cost per gigabyte \( \times \) gigabytes over. So equation: \( 25 + 15x = 70 \)

Step2: Solve for \( x \)

Subtract 25: \( 15x = 70 - 25 = 45 \)
Divide by 15: \( x = \frac{45}{15} = 3 \)

Step1: Define variable and equation

Let \( d \) be days. Cost for X: \( 50d \), Cost for Y: \( 30 + 30d \). Set equal: \( 50d = 30 + 30d \)

Step2: Solve for \( d \)

Subtract \( 30d \): \( 20d = 30 \)
Divide by 20: \( d = \frac{30}{20} = 1.5 \)

Step1: Define variable and equation

Let \( h \) be hours. Total earnings = monthly fee + hourly rate \( \times \) hours. Equation: \( 150 + 50h = 650 \)

Step2: Solve for \( h \)

Subtract 150: \( 50h = 650 - 150 = 500 \)
Divide by 50: \( h = \frac{500}{50} = 10 \)

Answer:

3 gigabytes

Problem 14