7th Grade Math

Test PracticeT

8. CHALLENGE When does a graph representing an inverse variation cross
   the x-axis? Explain.


9. OPEN ENDED Identify three sets of values of x and y for the inverse
   variation xy = 24.


10. E WRITE MATH Write a few sentences that compare and contrast
    inverse variation and direct variation.

C

14. TRAVEL A train traveled 203 miles in 1 _^12 hours.
    At this rate, how far will the train travel after 5 hours?
    Assuming that the distance traveled varies directly with the
    time traveled, write and solve an equation to represent the
    situation. (Lesson 3C)


15. STAMP COLLECTING Sun Li collects postage stamps from
    European countries. Use the graph to predict the number of
    postage stamps Sun Li will have in Year 10. (Lesson 3A)


16. Several people share twenty-five pieces
    of candy. If the situation is an inverse
    variation, which equation represents the
    situation?
    A. xy = 125
    B. y = _^25 x
    C. y = 125 x
    D. 25 x = y


17. Determine k if y varies inversely as x
    and y = 4.2 when x = - 1.3.
    F. - 3.27
    G. - 5.46
    H. - 0.31
    I. - 2.95


18. Identify the graph of xy = k if x = 2
    when y = 4.
    A. C.
    y

0 x

1

2

3

4

5

6

(^123456)
y
0 x
1
2
3
4
5
6
123456
B. D.
y
0 x
1
2
3
4
5
6
123456
y
0 x
1
2
3
4
5
6
123456
Lesson 3E Variation 415
Number of Stamps
60
40
20
0
1234567
80
100
120
Year
Postage Stamp Collection
404_415_C07_L3_895130.indd 415 12/31/09 4:33 PM