Author Topic: Random math question and my excel skills are failing me  (Read 967 times)

Gin1984

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Random math question and my excel skills are failing me
« on: November 11, 2020, 10:54:46 AM »
If you had two loan options, each for 10 years.  One was 3.25% all the way through and the other was 1.99% for the first year and 4% for the next 2 and then dropped to 3%, which would be the least cost?  And can someone walk me through how to do this in excel?

dandarc

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Re: Random math question and my excel skills are failing me
« Reply #1 on: November 11, 2020, 11:03:24 AM »
Is this a situation with a fixed payment? Such that both loans will be at $0 at the end of the term.

And are you asking in terms of nominal dollars out or inflation-adjusted, or something else?

Runrooster

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Re: Random math question and my excel skills are failing me
« Reply #2 on: November 11, 2020, 11:07:44 AM »
If you had two loan options, each for 10 years.  One was 3.25% all the way through and the other was 1.99% for the first year and 4% for the next 2 and then dropped to 3%, which would be the least cost?  And can someone walk me through how to do this in excel?

(1+.0325)^10 is the first loan =1.3768
(1+0.0199)(1.04)^2(1.03)^7 is the second loan =1.3567, this wins.

That's assuming you're not making payments on it.

dandarc

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Re: Random math question and my excel skills are failing me
« Reply #3 on: November 11, 2020, 11:13:37 AM »
I ran a quick amortization schedule assuming you make the same payment of $118.73 (the amount needed for a fixed payment for the level-rate loan to be zero at the end) in each scenario and it agree's with Runrooster's analysis that the more complicated interest rates are a bit less expensive than the flat rate.

When option A gets to $0, option B gets to ($8.90) if the starting balance was $1,000. So if you did this, you could have a fast-food lunch in ten years in addition to paying the loan off.

KarefulKactus15

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Re: Random math question and my excel skills are failing me
« Reply #4 on: November 11, 2020, 05:54:41 PM »
I just recently learned to use the PMT function.

This was way beyond what I could have figured out.