Precalculus

Cless_Alvein · October 18, 2003, 4:03pm

Consider your question:

-Daniel drives 15000 miles per year.
-The car he wants to buy is 20 mi/gallon
-Gasoline is $1.20/gallon

The question in the end asks how much mi/gallons the new car needs to save him 200 dollars. Now, I don’t know if you’ve mistyped the question or what, but you already gave me the answer when you said that the new car he wants to buy goes for 20mi/gallon. Do you mean the old car he has right now goes for 20mi/gallon?

Mastermune · October 18, 2003, 4:13pm

I did not mistyped anything in the excercise and i dont know how the others in the calass did it snce i did not go to school the last two days,all i remember them saying to me the first thing you do is 15,000/200 gives 900 and that is about what i remember.But i will get back to you when they tell me what the hell did they do it ok.

Cless_Alvein · October 18, 2003, 4:27pm

15000/20 * 1.2 is how much the car has to spend on gas $900 (and according to your question, the new car).

Now there seems to be only two possibilities:

You typoed. You meant to type that the old car gets 20 mi / gallon, so the old car actually spends $900 on gas per year, and that you don’t know the new car’s gas costs. In that case it would work like this:

15000/x * 1.2 = 700
18000/x = 700
18000 = 700x
x = 25.71 mi/gallon (approx). This would be the new car's minimum mi/gallon ratio.

This seems less likely, but Daniel really doesn’t know his old car’s miles/gallon, and he’s going to measure it and see if it’s worth it to buy a new car. In this case:

15000/x * 1.2 = 1100
18000/x = 1100
18000 = 1100x
x = 16.36 mi/gallon (approx). This would be the old car's maximum mi/gallon ratio.

So, which one is it? Solution #1 infers that you made a typo, and solution #2 is a very awkward and unlikely question.

Mastermune · October 18, 2003, 4:36pm

I will tell you as soon as i find out which might be on monday when i get the answer ok

Sinistral · October 19, 2003, 4:12pm

Nm what I wrote. Write out the questions verbatim, I’ll see if I can solve them. If my answers match cless’ , which they should, then you should be fine.

Mastermune · October 20, 2003, 1:21pm

Answer #1 it is but done in a diferent way(I checked and checked but i did’nt typoed)

(15,000/x=700/1.20)1.20(x)

18,000=700x

18,000/700=700x/700

x=25.7miles per galon

Cless_Alvein · October 20, 2003, 2:59pm

Uh, then yes, you did typo, if 25.7 is the answer.

2-Darnell drives about 15,000miles each year.he is planning to buy a new car.The car he wants to buy averages 20 miles on one gallon of gasoline.He has decided he would buy another car if he could save at least $200 a year in gasoline expenses.Assume gasoline costs $1.20 per gallon.What is the minimum number of miles per gallon that would fulfill Darnell’s criteria?

You meant to say that the car he has average 20 miles on one gallon.

Mastermune · October 20, 2003, 3:07pm

But i did not i got the book right in my hands this moments and that is how it says it,maybe it was the books mistake since the one i have tends to have some mistakes

Heaven_s_Soldier · October 21, 2003, 9:36am

If the book was finished quickly then it will have mistakes. The one I have is full of them, just because they needed it out in time.

Videospirit · October 21, 2003, 10:06am

Are you sure the book doesn’t want you to round your answers up? that would get you the answer of 8.

BahamutXero · October 21, 2003, 12:44pm

I’ve taken college Business Calculus but as of now all I’m good for is basic algebra. I guess I know where I’m coming if I need help. Great job Cless.