Question

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

Answer 1

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

Answer 2

Let x be the smaller number.
Then 3x is the larger number.
We also know that the smaller added to the larger is 52, or:
x + 3x = 52
4x =52
x = 13
Therefore the smaller is 13, the larger is 3(13)=39.