Which of the following equations describes the table below?

a. y = -3x - 1/4
b. y = 4x - 3
c. y = -1/4x - 3
d. y = 1/4x - 3

answer:  

\boxed {\frac{1}{5}}  

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solution-

60 *   \frac{1}{5}   = 12

90 * \frac{1}{5} = 18

75 * \frac{1}{5} = 15

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hence, the answer would be \boxed {\frac{1}{5}}