A disk of radius 3 cm has density 12 g/cm2 at its center, density 0 at its edge, and its density is a linear function of the distance from the center. Find the mass of the disk.

The correct option is 4.

Step-by-step explanation:

Let the number of sheep be x and the number of chickens be y.

It is given that there are total 16 animals.

          .... (1)

The number of chickens, y, is 4 less than the number of sheep, x.

           .... (2)

Using (1) and (2), we get

Add 4 on both the sides.

Divide both sides by 2.

Put x=10 in equation (1).

Subtract 10 from both the sides.

The ordered pair (10,6) represents the number of chickens and sheep. Therefore the correct option is 4.