
William W. answered 01/12/20
Top ACT Math Prep Tutor
Let hc be the hours Leland works at the car wash. So the amount he earns at the car wash = 10hc ($10/hour times the number of hours).
Let hs be the hours Leland works at sitting. So the amount he earns at babysitting = 12hs ($12/hour times the number of hours).
The total amount he earns for both jobs is 10hc + 12hs and that he plans it to be more than $450. So we can say 10hc + 12hs > 450
We are also told that he plans to work "at most" 40 hours so that means hc + hs < 40.
We can graph hc and hs on a graph with each one being an axis. Let's let hc be the x-axis and hs be the y-axis. It might help to build a table.Since the "equal" condition is the boundary for the inequality. We'll build a table for that "equal" condition.
For the amount earned (let 10hc + 12hs = 450), the table looks like this:
hc hs amount earned
0 37.5 450
45 0 450
For the hours worked (let hc + hs = 40), the table looks like this:
hc hs total hrs worked
0 40 40
40 0 40
Now, graph these and shade the appropriate parts (for the amount earned, we shade above the line because we want the amount earned to be greater than $450. For the number of hours worked, we shade below the line because we want the total hours worked to be less than or equal to 40). We also use a solid line for the hours worked because in can be 40. We use a dotted line for the dollars earned because it cannot be 450 (must be greater than).
Key: Blue represents the hours he needs to earn more than $450. Violet represents the hours worked less than 40. Red is the overlapping area or the hours that will be less than 40 but earn him more than $450.
Eva N.
thanks ur the best, this is a great explanation!01/13/20