thexxx wrote:
ScottTargetTestPrep wrote:
ganand wrote:
Of the 150 houses in a certain development, 60 percent have air-conditioning, 50 percent have a sunporch, and 30 percent have a swimming pool. If 5 of the houses have all three of these amenities and 5 have none of them, how many of the houses have exactly two of theseamenities?
(A) 10
(B) 45
(C) 50
(D) 55
(E)65
We can create the following equation:
Total houses = number with air conditioning + number with sunporch + number with pool - number with only two of the three things - 2(number with all three things) + number with none of the threethings
150 = 0.6(150) + 0.5(150) + 0.3(150) -D - 2(5) +5
150 = 90 + 75 + 45 - D - 10 + 5
150 = 205 - D
D = 55
Answer:D
Hello to everyone and thanks for the explanation. I still got a doubt on the formula i highlighted, especially on the -D.
In the -D what we need to put, if we are request to find the -D? the sum of all the 3 group that overlaps with 2 element or only one of the 3 group that overlaps with 2elements?
thanks
That
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Statistics : Posted by Bunuel • on 29 May 2017, 03:27 • Replies 24 • Views 94875
