# algebra

posted by
**stressed**
.

I have no clue what to do here can you tell me how to figure this?

If y varies directly with x, and y = 500 when x = 200, find the constant of variation k.

Whenever you have a statement such as

"....y varies directly with x..."

you can write it as an equation y = kx, where k is some constant

so in your case they give you x=200, y=500

sub those values into the equation and you can solve for k

This is an example of a direct variation.

You can also have an "inverse variation", such as...

"The Time taken for a trip varies inversely with the speed"

then your equation would be Time = k(1/speed), again where k is some constant.