The 15 homes in a new development are each to be sold for one of three different prices so that the developer receives an average (arithmetic mean) of $200,000 per home. If 4 of the homes are to be sold for $170,000 each and 5 are to be sold for $200,000 each, what will be the selling price of each of the remaining 10 homes?
Choose the most appropriate option
A) $200,000  B) $212,000  C) $215,000  D) $220,000  E) $230,000
IMO the answer has to be D.   5 houses are being sold for 200,000. 4 houses are being sold for $30,000 less, resulting in a loss of $120,000. To make the average selling price intact i.e. $200,000, the remaining 10 houses must be sold at such a profit that it compensates for the loss of 120,000. Hence 10x=120,000.   x=12,000.   The 10 houses are sold at $12,000 profit or at $212,000. (ANSWER $212,000)
<result>B</result>
The 15 homes in a new development are each to be sold for one of three different prices so that the developer receives an average (arithmetic mean) of $200,000 per home. If 4 of the homes are to be sold for $170,000 each and 5 are to be sold for $200,000 each, what will be the selling price of each of the remaining 10 homes?