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View Full Version : Finding the missing number when the average is known


nzavala
Oct 14, 2007, 05:00 PM
I need to know if there is an easier way to solving this problem.

Three homes on Lavender Lane recently sold for an average price of $89,000. Two of the homes sold for $95,000 each. What is the price of the third home?

Answer: I know that $95,000 + $95,000= $190,000

If I use random numbers between $76,000 to $80,000, I'm going to narrow my answer to $77,000. By adding $95,000 + $95,000 + $77,000 = $267,000

Then I divide $267,000/3= $89,000. So third home costs $89,000.

Is there a better way to solving these types of problems? My way takes too long to solve.

Any ideas are welcome.

cool_dude
Oct 14, 2007, 06:25 PM
off course there's a better way then guess and check. Make an equation. (2(95000) + x)/3 = 89000 now just solve for x which is the price of the third house

InfoJunkie4Life
Aug 19, 2010, 01:16 PM
You know that the average is 89000. If there were 3 numbers then you know the big number was divided by 3 to get 89000. So if you take 89000 and multiply it by 3, you can subtract what numbers you know to determine the remaining number.

(Basically the same thing proposed above)