SOLUTION: If x varies inversely as y and x = 2 when y = 8, find x when y = 15. PLEASE HELP

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Question 93430This question is from textbook
: If x varies inversely as y and x = 2 when y = 8, find x when y = 15. PLEASE HELP This question is from textbook

Found 2 solutions by jim_thompson5910, Earlsdon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
When x varies inversely with y, you simply have this relationship
y=k%2Fx

8=k%2F2 Plug in x=2 and y=8

8%2A2=k Multiply both sides by 2

16=k Multiply

So our equation is y=16%2Fx


Now plug in y=15 to find x

15=16%2Fx

15x=16 Multiply both sides by x

x=16%2F15 Divide both sides by 15

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You can write this relationship (formula) as:
x+=+k%2Fy x varies inversely (upsidedownwardly ?) as y which really means that if y goes up then x goes down and vice versa. The k is called the proportionality constant.
We need to determine the value of k. This can be done with the help of the given information that x = 2 when y = 8. Substituting these values into the above equation allows us to solve for k.
2+=+k%2F8 Multiply both sides by 8.
2%288%29+=+k so...
k+=+16
Now our formula looks like this:
x+=+16%2Fy
Now we are ready to answer the question: What is x when y = 15.
x+=+16%2F15
x+=+1.067