Respuesta :
To determine the number of whole hours Ruby must work washing cars to meet her requirements, let's break down the given information step by step:
1. Ruby can work at most 18 total hours in a week.
2. Ruby must earn a minimum of $180.
3. Ruby earns $12 per hour washing cars and $8 per hour walking dogs.
4. Ruby already worked 3 hours walking dogs.
To find the possible values for the number of whole hours Ruby must work washing cars, we need to consider two scenarios:
Scenario 1: Ruby works the maximum number of hours washing cars.
In this scenario, Ruby would work for the remaining hours after subtracting the hours she already worked walking dogs. Therefore, the number of hours Ruby would work washing cars is: 18 total hours - 3 hours walking dogs = 15 hours.
Scenario 2: Ruby works the minimum number of hours washing cars.
In this scenario, Ruby would work the minimum number of hours needed to meet the minimum earnings requirement of $180. To calculate this, we can set up an equation:
$12 per hour (washing cars) * x hours (washing cars) + $8 per hour (walking dogs) * 3 hours (walking dogs) = $180.
Simplifying the equation:
12x + 8(3) = 180
12x + 24 = 180
12x = 180 - 24
12x = 156
x = 156 / 12
x = 13
So, Ruby would need to work a minimum of 13 whole hours washing cars to meet her requirements.
Therefore, the possible values for the number of whole hours Ruby must work washing cars to meet her requirements are 15 hours (in scenario 1) and 13 hours (in scenario 2).
