Answer:
d. 1 grid equals 1 hour
Step-by-step explanation:
When plotting research data, X-axis(or horizontal axis) usually used for independent variable and Y-axis is used for the dependent variable. In this case, Heather wants to know how much earning on different numbers of hours. The dependent variable is the earning and the independent variable is the hours, so you put hours on the horizontal axis.
You want to make a 10x10 grid of data and the hours ranged between 1-10. If you plot them equally, approximate scale will be: (10h-1h)/(10)= 0.9h/grid
The closest option is 1 hour per grid. It will provide the best visualization since it won't stretch or minimize the data too much.
The slope is defined as

So, we have the follwing equation:

I’m not 100% certain but i’m pretty sure 1:3 works
The answer is number 4 "You have $60 to spend on hats at the mall, but you need to save at least $7 for lunch. You plan to spend the rest on hats that cost $15 each including tax"
60-$15x refers to "you have $60 to spend on hats" and "to spend the rest on hats" while <7 for ''save at least $7 for lunch"