SOLUTION: For a car loan using simple interest at a given​ rate, the amount of interest charged varies jointly with the loan amount​ (also known as the​ principal) and the time of the

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Question 1179485: For a car loan using simple interest at a given​ rate, the amount of interest charged varies jointly with the loan amount​ (also known as the​ principal) and the time of the loan​ (in years). If a $15,000 car loan earns ​$2100 in simple interest over 5 ​years, how much interest will a ​$32,000 car loan earn over 7 ​years?
Found 4 solutions by mananth, MathTherapy, greenestamps, ikleyn:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!

If a $15,000 car loan earns ​$2100 in simple interest over 5 ​years, how much interest will a ​$32,000 car loan earn over 7 ​years?
Simple Interest = P * T * R
2100 = 15000 *8*r
2100/(15000*8)=0.0175====> 1.75%

32000 , 7 years, 1.75%
Simple Interest = 32000*7*1.75


Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
For a car loan using simple interest at a given​ rate, the amount of interest charged varies jointly with the loan amount​ (also known as the​ principal) and the time of the loan​ (in years). If a $15,000 car loan earns ​$2100 in simple interest over 5 ​years, how much interest will a ​$32,000 car loan earn over 7 ​years?
The interest rate is NOT 1.75%. It's actually 2.8%. 

So, ignore that answer by the other person.



For the INSECT on top of the HILL!

I wish the OLD, OVER-THE-HILL, racist would just DISAPPEAR. He seems to be UNABLE to come to the forum without having something wise (actually FOOLISH) to say!

I wish the INSECT would just DISAPPEAR! Other people on here don't seem to want to speak up against this self-professed know-it-all NINCOMPOOP!

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The response you should ignore is the one from tutor @MathTherapy, since it contains nothing that helps YOU learn how to solve the problem.

Instead, use the method shown by the other tutor; but use the correct given information.

i = prt
2100=(15000)(r)(5)
2100=75000r
r=75000/2100=0.028 or 2.8%

Then apply that interest rate to the new set of numbers:

i = prt
i = (32000)(0.028)(7)

You can do the calculation to finish the problem.

Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.


            Thanks to tutor @MathTherapy, who noticed/detected the  FATAL  ERROR  in the @mananth solution.

            Thanks to tutor @greenestamps,  who presented an improved solution.

            Since the writing by @greenestamps is still not free of errors,  I came to further improve it. 


i = prt

2100=(15000)(r)(5)

2100=75000r

r=2100/75000=0.028 or 2.8%.     <<<---===  it is where I edited the solution by @greenestamps 



Then apply that interest rate to the new set of numbers:

i = prt

i = (32000)(0.028)(7) = 6272  dollars.      ANSWER

                Hope everything is  OK  now.


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There are several so called  "tutors"  at this forum,  who produce huge number of erroneous solutions every day.

Thanks to other tutors who relentlessly check all the solutions.

Every found error is an invitation to other tutors to provide better response to our valuable visitors.


It is why I highly appreciate the work by  @MathTherapy.


I think,  everyone,  including all our visitors,  join me to thank him.


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As I worked in Science and Engineering for many years, I know that checking and cross-checking of calculations,
memos, reports, and articles is very usual, routine and necessary procedure.

The authors are always thankful to their colleagues - reviewers and checkers, who provide checks and reviews to their products.