ANSWER
1) 12
EXPLANATION
The interquartile range is the difference between the third quartile and the first quartile.
The second quartile Q2 is the median of the data set:
[tex]Q_2=\frac{25+28+32+35+36+40+46}{7}=\frac{242}{7}=35.57\approx35[/tex]The first quartile Q1 is the median of the first half of the data set, not including Q2: 25, 28, 32:
[tex]Q_1=\frac{25+28+32}{3}=\frac{85}{3}=28.333\approx28[/tex]The third quartile is the median of the second half of the data set, not including Q2: 36, 40, 46:
[tex]Q_3=\frac{36+40+46}{3}=\frac{122}{3}=40.666\approx40[/tex]The interquartile range IQR is:
[tex]\text{IQR}=Q_3-Q_1=40-28=12[/tex]