if x varies directly to y, and x=3 when y=18, what is the constant of variation?

Your answer is going to be : 6 cause 6 x 3 = 18

x varies directly to y means x=ky (and y varies directily to x means y=kx, so diffent) x=3 and y=18 x=ky 3=k18 divide both sies by 18 1/6=k the constant of variation is 1/6