Lotana,

As far as I'm concerned, you ACED it!!! $20 out? I was happy to get as close as I did, but you hit the bullseye in my opinion. Congratulations!!

Now, a lucky guess would not have counted, but your workings showed a very realistic approach. Well done, GURU !!

I'll use your "worksheet" (slightly modified) to reflect how I arrived at my answer too (hope you don't mind).

1. Since we are valuing an even number and our stats contain just one odd number we dismiss it. Then capitalise repairs:

**Les>> Agree completely**
2. Knowing property appreciation rate, we standardise historical prices to the month of December (i.e. how much would a property be in December).

**Les>> Agree - except I compounded monthly, instead of "straight-line"**
This results in the following:

House No.-- Months - Rate -- Future Value - Les% -----Les Value

No.20--------11--------2.75%-----$236,325 -- 0.25%pm--236404

No.46--------3----------0.75%-----$216,108-- 0.25%pm--216113

No.66--------9----------2.25%-----$206,545-- 0.25%pm--206591

3. December value for house 54 can be calculated using straight line interpolation between houses 20 and 66 and 46 and 66 and then avaraging the two estimates.

**Les>> This is where we diverge somewhat. I used a kind of "straight-line", but got the impression that lower numbers increased more exponentially than straight-line**
So, first I noted "average growth per house" between 20 and 46 was $1560.84 while "average growth per house" between 46 and 66 was only $952.20 - this tells me that "straight-line" is not the answer, and that growth is more exponential.

Since I don't know how to do exponential calculations, I took a few "punts" - expecting to get within a few dollars anyway.

So, given that the AVERAGE growth per house between 46 and 66 was $952.20, I can be reasonably sure that 56 would be pretty close to average (probably a little less) - and that price is (before repairs) $211352.

Now - #56 price of $211352 is probably a little higher than it should be (I've used "straight-line" to arrive at this figure - and, if exponential, it's value will actually be somewhat lower (a few dollars)

** And HERE is where I stuffed up - leaving my price much lower than it should have been**
#54 is going to be higher than #56 - I had been using "street numbers" rather than houses, and when allowing for the house next door to #56, I only allowed one house number, instead of 2. So, my answer should have been $211352 + $952.20 (less repairs) or $152304 rather than $151829.

.....still well short of Mike's answer - so, not sure where the difference lies. I'm interested to see the answer. Any "exponential differences" should see this figure get LOWER, not higher

And, Lotana, even though your worksheet showed a figure higher than you originally posted, it was still closer than my original, or revised, figure. Were you going for a "bargain", guru?

Whatever, it was a bit of fun - thanks, Mike - looking forward to how you got what you did as an answer ....