Question

Vincent is calculating values for a direct variation which has a constant of variation of k=13.

Which pair of values in the table below did Vincent calculate incorrectly?

x 3 6 9 12
y 1 2 6 4

Answer 1

(9,6)

Let's verify

find k

• k=y/x
• k=1/3

So

• 6=1/3(9)
• 6≠3

Hence it's incorrect

Answer 2

• (9, 6) is incorrect

Explanation:

It seem the constant of variation is k = 1/3.

The equation is:

• y = kx or
• y = 1/3x

Let's verify the values in the table:

• 1 = 3*1/3 ⇒ 1 = 1, correct
• 2 = 6*1/3 ⇒ 2 = 2, correct
• 6 = 9*1/3 ⇒ 6 = 3, incorrect
• 4 = 12*1/3 ⇒ 4 = 4, correct