Posted by **bobpursley** on Wednesday, May 23, 2007 at 9:56pm.

I will be happy to critique your thinking.

can u use one of them and show me how to solve it and i'll do the rest? like i don't know how to do these and i need to know how.

assume that Q varied directly as x and inversely as y.

1) if x is tripled and y is doubled, what happens to Q?

2) if x is halved and y is doubled, what happens to Q?

3) if x is doubled and y is halved, what happens to Q?

4) in the formula F=m times pi times l squared over p, m and pi remain constant, l is halved, and p is doubled. how does F change?

Take number two.

Q varies directly as x and inversely as y. That means Q= k x/y where k is some constant.

If x is halved, and y is doubled..

reducing x by one half means q is reduced by one half. But y is doubled, which means x is halved again (q=k x/y)

So Q goes down to 1/4 or 1/2 *1/2 of the original.

Lets do it the math way now.

Let Qo be the value of kx/y

Q' is the new value.

Q' = k (1/2 x)/2y = 1/4 k x/y=1/4 Qo

so that means the last one, Q is didided by 4?

i don't understand how Q changes can u explain