SOLUTION: How do I do tis? If x varies directly as y, ad x=20 when y=4, find x when y=9. A. x=80 B. 36 C. x=180 D. x=45

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Question 874448: How do I do tis?
If x varies directly as y, ad x=20 when y=4, find x when y=9.
A. x=80
B. 36
C. x=180
D. x=45
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

Let k represent the constant of the direct variation

 x = ky

20 = 4k

 5 = k

x = 5y

x = 45 when y = 9