If two-thirds of Sam's weekly income is $480, what is one-fourth of his weekly income?

To find the full amount of their pay divide $480 by 2/3:

480 / 2/3 = 480 * 3 / 2 = 1441/2 = $720

Now you have the weekly pay, divide by 4 to find 1/4 of it:

720 / 4 = 180

one-fourth of his pay is $180.