Answer:
The Sum of two number is 15: x + y = 15
One of the numbers is 12 times the other: x = 12y:
System of equations:
x + y = 15
x = 12y
Plug x = 12y into equation one(x + y = 15)
12y + y = 15
13y = 15
y = 15/3
y ≈ 1.15
Now we know x = 12y
x = 12(15/13) = 180/13
x = 180/13
x ≈ 13.85
The biggest number is x = 180/13.