x = Bigger number is 5/3
y = Smaller number is 1/3
Solution
x = 5y
x + y = 3 - 3y which is x + 4y = 3
So, then replacing x with 5y in the second equation we get
5y + 4y = 3
So y = 1/3
Then coming back to the first equation
x = 5/3
Check the result with the second equation
5/3 + 1/3 = 3 - 3/3