<p>A data set has 15 elements. The 15 elements in a second data set are obtained by multiplying each element in the first data set by 10. The 15 elements in a third data set are obtained by decreasing each element of the second data set by 20. The median of the third data set is 50. What is the median of the first data set?</p>
<p>a. -20
B. 7
C. 50
D. 70
e. 750</p>
<p>Data sets</p>
<p>X Y Z</p>
<hr>
<p>X 10X 10X-20</p>
<p>So… 10X-20 = 50
10X = 70
X = 7</p>
<p>So B? Is that right?</p>
<p>yep, that’s right. I get the x, 10x, and 10x-20…but why do you set 10x-20 = 50? I know that it says the median of the third set is 50, but I guess I just don’t get it…</p>
<p>here’s another that’s almost identical but I still dont get it:</p>
<p>Each number on a list containing 100 numbersis divided by 10 to producea second list containing 100 numbers. Each of the 100 numbers on the second list is decreased by 2 to produce a third listof 100 numbers. The median of the third list is x. Which of the followeing expressionsgives the median number of the original list?</p>
<p>a. x/10-2
b. x/10
c. x+2
d. 10x+2
e. 10( x+2)</p>
<p>First -> Second
Divide by 10
Second -> Third
Subtract 2</p>
<p>Third data set = X</p>
<p>Third -> Second
Add 2
X + 2
Second -> First
Multiply by 10
10(X + 2)</p>
<p>e.</p>
<p>got it, thanks!</p>