Direct variation y = kx and inverse variation xy = k

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. Read this first

   Input–output table

   x	y
   3	15
   8	?

2. 1.

   Kira knows y varies directly with x, and y = 15 when x = 3. What is y when x = 8?

   40
3. 2.

   Kira knows y varies directly with x, and y = 6 when x = 4. What is y when x = 14?

   21
4. 3.

   Kira knows y varies directly with x, and y = 9 when x = 2. What is y when x = 6?

   27
5. 4.

   Ren knows y varies directly with x, and y = 8 when x = 5. What is y when x = 15?

   24
6. 5.

   Noah knows y varies inversely with x, and y = 12 when x = 3. What is y when x = 9?

   4
7. 6.

   Ari knows y varies inversely with x, and y = 15 when x = 4. What is y when x = 6?

   10
8. 7.

   Luz knows y varies inversely with x, and y = 18 when x = 2. What is y when x = 12?

   3
9. 8.

   Tala knows y varies inversely with x, and y = 8 when x = 5. What is y when x = 20?

   2
10. 9.

    Jun fills in a table of a rule, shown in the figure. Is y direct variation, inverse variation or neither?

    • Inverse variation
    • Direct variation
    • Neither
11. 10.

    The rule is y = x/4. Bo meets the rule y = x/4. Is y direct variation, inverse variation or neither?

    • Direct variation
    • Neither
    • Inverse variation