SOLUTION: x varies inversely with y. When x is 40, y is 50. What is y when x is 25?

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Question 242972: x varies inversely with y. When x is 40, y is 50. What is y when x is 25?
Found 2 solutions by nerdybill, Edwin McCravy:
Answer by nerdybill(7384)   (Show Source): You can put this solution on YOUR website!
From:
x varies inversely with y
we have
x = k/y
.
From:
When x is 40, y is 50
we have
40 = k/50
40*50 = k
2000 = k
.
So, when x is 25
25 = 2000/y
25y = 2000
y = 80

Answer by Edwin McCravy(20054)   (Show Source): You can put this solution on YOUR website!
x varies inversely with y.

That says  

When x is 40, y is 50.

With that information we can determine k:





Multiply both sides by 50





Now we must substitute that value 
of k into 

Now we have the complete equation.



Now with that complete equation we can answer
the other part:

What is y when x is 25?



Substitute 25 for x



Multiply both sides by y









Edwin

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