How do you figure 12 is 30% of what number

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?

The constitution gives congress the power to create federal courts lower than the supreme court higher than the supreme court equal to the supreme court, unaffected by the supreme court.

Which equation is equivalent to the given expression? -(1/2y+1/4) a. -1/4(1+2y) b. 1/4(2y-1) c. -2(1/4y-1/8) d. 2(1/8-1/4y)