Question Below!

Question

The variable Z is directly proportional to X, and inversely proportional to Y. When X is 6 and Y is 3, Z has the value 6.

What is the value of Z when X = 10, and Y = 8

Answer 1

I wonder if the question is worded clearly.  There is enough ambiguity in the wording that probably no one wants to take a chance wasting their time on it.

 

Let me re-word it.  I think there might be two parts:

 

Part 1: The variable Z is directly proportional to X.  When X = 6, Z = 6.  What is the value of Z when X = 10 ?

 

Z = k X

 

 

Z = k•X  =  6

 

k = 1

 

The value of Z when X = 10 is Z = k X  =  1 (10) = 10.   (I think)

 

Now for the other problem .......

 

The variable Z is inversely proportional to Y.  When Y is 3, Z = 6.  What is the value of Z when Y = 8 ?

 

Z = k/Y

 

Z = k / 3 = 6

 

k = 18

 

When Y = 8,  Z = 18/8 = 9/4 = 2.25.  (I think)