# Thread: Worded linear equation problem.

1. ## Worded linear equation problem.

The cost of hiring a car for a day is £50 plus £0.55 per mile travelled. If £y is the cost of hiring a car for a day and x is the number of miles travelled write down the relationship between x and y. Draw the line represented by this equation, identifying the gradient and intercept. If the car is driven 350 in a day, what is the cost of hire? How far can I travel for £150?

2. You are just asked to setup a function. What you need to do is to write down:

y(x) = "fixcost" + "cost per mile" * x. Then you need to solve this for x = 350. For the second question set y = 150 and solve for x.

3. I'm totally confused... don't I need to do it in a graph?

4. Originally Posted by mathsnub
I'm totally confused... don't I need to do it in a graph?
you can read the answer from the graph once you have established the relationship or you can substitute in the values.

5. This right then?

350*0.55 = £192.50 + £50 = £242.50. Thats the cost for 350 Miles a day.

150-50 = 100. 100/0.55 = 181.81 Miles. Thats the amount of miles for £150.

6. Originally Posted by mathsnub
This right then?

350*0.55 = £192.50 + £50 = £242.50. Thats the cost for 350 Miles a day.

150-50 = 100. 100/0.55 = 181.81 Miles. Thats the amount of miles for £150.

yep.

7. Any way I can input all of this into excel to make a graph?

I have no idea on where to start

8. As far as I know you can plot such functions in Excel without giving values. There are many programs however, that do the same job. If you use a Mac e.g. Grapher is installed on your system. For Windows there exists plenty of freeware.

If you want to draw it on paper, however: This function is linear. That means that it will be drawn as a line since the relative change from x to y remains the same over all values of the function. Calculate two random values (what you already did) and draw a line that connects both points. This will be your graph of the function.

What do I actually input in excel? How do I write it etc as I have no idea lol

10. I dont use Excel myself but if you enter plot function into Google you will find plenty of online tools. What is wrong with just drawing it? All you need for that is a ruler.

11. what numbers do I put on the x and y axis? I have no clue on how to draw the graph. Not done Maths in years!

Need help drawing it lol

12. Take the two points you calculated (any other points would do it) and connect them as a line.

13. What does the y and x axis go up in?

14. This is pretty basic so I just attached the picture.

15. Originally Posted by mathsnub
What does the y and x axis go up in?
You only need to worry about the increment in x, y will be dependant on that. Book1.xls