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The IQR is the difference between Quartile 1 and Quartile 3
Q 1 = 17 and Q 3 = 30
Q3 - Q1 = 30 - 17 = 13
|-1/5| < |-1/3| < |-7|
Your answer:
B. y = -1/5 x^2; y = -1/3 x^2; y = -7x^2
Look at the picture.