My Math Forum  

Go Back   My Math Forum > High School Math Forum > Geometry

Geometry Geometry Math Forum

LinkBack Thread Tools Display Modes
December 13th, 2013, 07:31 AM   #1
Joined: Dec 2013

Posts: 2
Thanks: 0

Easy Analytical Geometry

A car rental firm has the following charges for a certain type of car: $25 per day with 100
free miles included, $0.15 per mile for more than 100 miles.

Suppose you want to rent a car for one day, and you know you’ll use it for more than 100 miles.
What is the equation relating the cost y to the number of miles x that you drive the car?

For the life of me I can't understand how to get the formula in the back of the book. I am not in school currently, but I am reviewing my Calculus in preperation for Cal II.

The formula they give as an answer is:
y = 0.15x + 10

I don't understand where the 10 comes from and how they incorporate the $25 charge. Please break this down for me, I'm sure I'm just over complicating it.
jSasor is offline  
December 13th, 2013, 08:52 AM   #2
Senior Member
MarkFL's Avatar
Joined: Jul 2010
From: St. Augustine, FL., U.S.A.'s oldest city

Posts: 12,211
Thanks: 520

Math Focus: Calculus/ODEs
Re: Easy Analytical Geometry

I would begin with:

Now distribute the 0.15:

Combine terms and arrange in slope-intercept form:

MarkFL is offline  
December 13th, 2013, 09:24 AM   #3
Joined: Dec 2013

Posts: 2
Thanks: 0

Re: Easy Analytical Geometry

Wow. You've definitely cleared that up for me. I should have put in a little more effort on this one.
I really appreciate it, Mark.
jSasor is offline  

  My Math Forum > High School Math Forum > Geometry

analytical, easy, geometry

Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Analytical Geometry: Parallel line and plane tomkoolen Geometry 0 January 24th, 2013 02:42 PM
tips to make geometry easy mrhesham Academic Guidance 1 December 29th, 2010 07:10 PM
Analytical Geometry julian21 Geometry 2 July 17th, 2010 01:06 PM
An Easy Geometry Question n3rdwannab3 Geometry 2 May 3rd, 2010 02:25 PM
Analytic geometry semi-easy nortpron Geometry 3 April 3rd, 2010 04:32 AM

Copyright © 2019 My Math Forum. All rights reserved.