Answers:
R can be either 8, 9 or 10
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Explanation:
Let's exclude the R value for now.
The set {4,13,5,8,5,11} sorts to {4,5,5,8,11,13}.
Now we'll include R back in. We're told that R is an integer and it's smaller than 11. The possible values R can take on are: {10, 9, 8, 7, ...} The countdown continues forever into the negative territory.
If R < 4, then we go from {4,5,5,8,11,13} to {R,4,5,5,8,11,13}. That R is guaranteed to be the min value since R is less than the smallest value of the previous set. Note that the middle-most item of the second set is 5; however, we want the median to be 8 instead. This allows us to rule out the case that R < 4.
So we've determined that 4 < R < 11. Because R is an integer, we can say it takes on the values from the set {5,6,7,8,9,10}
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If R = 5, then {4,5,5,8,11,13} updates to {4,5,5,5,8,11,13} after adding in that R value. We can see the median is 5, so we can rule out the case that R = 5.
Similarly, we can rule out R = 6 as well. The set {4,5,5,8,11,13} updates to {4,5,5,6,8,11,13} in which the median is 6.
If R = 7, then the median is 7 for similar reasoning and we can rule out this R value.
So we've ruled out the cases that R = 5, R = 6 and R = 7.
If we tried R = 8, then {4,5,5,8,11,13} becomes {4,5,5,R,8,11,13} = {4,5,5,8,8,11,13}. This set has a median of 8 and R = 8 is one of the answers.
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Now let's consider the possibility that 8 < R < 11.
If for instance R = 9, then {4,5,5,8,11,13} becomes {4,5,5,8,9,11,13} to show that this set also has a median of 8. R = 9 is another answer.
The same idea happens when R = 10 as well because we get {4,5,5,8,10,11,13}. R = 10 is another answer.
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In short, R can be any of the following values: <u>8, 9, 10</u>
