Find the perimeter of PAW

The larger number is 12 and the smaller number is 9

Step-by-step explanation:

Let us first deal with the first sentence of this word problem.

Let's call the larger number  L

and the smaller number  S .

We know from the first sentence:

3 L  = 4 S

We know from the second sentence:

L+S  = 21

Let's solve this second equation for  

L- L+S  = 21 - L

S  = 21 - L

Now we can substitute  21 - L for S  in the first equation and solve for  L :

3L = 4 (21 - L)

3L + 4L = 84 - 4L + 4L

7L = 84

7L/7 = 84/7

L = 12

Next we can substitute 12 for L in the solution to the second equation:

s = 21 - 12

s = 9