Question

If y varies inversely with x, and y = -3 when x = 18, find x when y = -2

A: -33
B: 27
C: -6
D: -12

Answer 1

The correct answer would be 12, which isn't one of your options.

Explanation:

When finding direct variation, you start with the base equation.

y = kx

Now we can use the initial values of x and y to find k.

-3 = k(18)

-1/6 = k

Now with the value of k, we can model the equation.

y = -1/6x

And we can find the new x by using our new value of y.

-2 = -1/6x

12 = x