Please help me solve this problem

D

Dominic

Junior Member
Joined
Jun 16, 2005
Messages
69
Assume that Y varies inversely as X. If Y=8 when X=2.5 , find X
when Y=2.
 
"Y varies inversely as X" means:

. . . . Y = k / X for some constant k

Plug in Y = 8, X = 2.5, and you can solve for k. Then let Y = 2, and solve for X.
 
Dominic said:
Please correct me if I'm wrong. My answer is 10.
Click to expand...
That's what I get. What did you get for 'k'?

P.S. It always helps to show your work. The answer is NOT as important as your thinking process. (Although, and sadly, many teachers get in a hurry and forget that concept.)
 
I worked out this problem like this:

2.5 * 8 = 20/2

So K is 20

Then I divided 20 into 2 and got 10.
 
Did you, at any time, actualy write down:

y = 20/x

??

You have demonstrated nicely why showing your work is important. You said you "divided 20 into 2", but that cannot be what you did. Nevertheless, you managed the correct result, x = 10.

If you deliberately write down the equation, if you deliberately and carefully substitute the known value, if you then deliberately and consistently solve for the remaining value, THEN one can know of assurety one of two things, 1) The answer is correct, or 2) We can go back and figure out where we went wrong.
 
tkhunny said:
Did you, at any time, actualy write down:

y = 20/x

??

You have demonstrated nicely why showing your work is important. You said you "divided 20 into 2", but that cannot be what you did. Nevertheless, you managed the correct result, x = 10.

If you deliberately write down the equation, if you deliberately and carefully substitute the known value, if you then deliberately and consistently solve for the remaining value, THEN one can know of assurety one of two things, 1) The answer is correct, or 2) We can go back and figure out where we went wrong.
Click to expand...

Sorry about that I meant to say 20/2 and my answer was 10
 
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