Re: The numbers of cars sold at a certain dealership on six of t
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20 Aug 2020, 13:26
Let x= # of cars sold in the seventh day
x can be 2, 4, or 5
We have
4,7,2,8,3,6,x
Let's put the list in order
2,3,4,6,7,8,x
The average number of cars sold per day is
=(2+3+4+6+7+8+x)/7
=(30+x)/7
We want to find for which value of x will
(30+x)/7 = median of the list
Case 1: x=2
Our list becomes
2,2,3,4,6,7,8
(30+x)/7=(30+2)/7= 32/7
Median= 4
32/7 does not equal 4
Therefore x does not equal 2
Case 2: x=3
Our list becomes
2,3,3,4,6,7,8
(30+x)/7=(30+3)/7= 33/7
Median= 4
33/7 does not equal 4
Therefore x does not equal 2
(At this point we know the answer must be only x=5, since it is the only one left. We'll check it either way)
Case 3: x=5
Our list becomes
2,3,4,5,6,7,8
(30+x)/7=(30+5)/7= 35/7 =5
Median: 5
5=5
Therefore x equals 5
Final Answer: B