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.

   Esme knows y varies directly with x, and y = 15 when x = 6. What is y when x = 8?

   20
5. 4.

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

   10
6. 5.

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

   3
7. 6.

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

   2
8. 7.

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

   • Direct variation
   • Neither
   • Inverse variation
9. 8.

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

   • Neither
   • Inverse variation
   • Direct variation
10. 9.

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

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

    The rule is y = 2x/3. Milo meets the rule y = 2x/3. Is y direct variation, inverse variation or neither?

    • Inverse variation
    • Direct variation
    • Neither