The sum of two numbers is 52. one number is 3 times as large as the other. what are the numbers?

Let b>a

b+a=52 

b=52-a, we are also told that the larger number, b, is 3 times the smaller a:

b=3a, since b=b we can say:

3a=52-a 

4a=52

a=13, and since b=3a

b=39

So the numbers are 13 and 39

Ithink it's the first one ( let me know if it right)