The difference of two numbers is more than 12,and one of the numbers is 3

X+y = 12
x-y = 3
x = 3+y

Substitute it in 1st equation,
3+y+y=12
2y = 9
y = 4.5

Substitute it in 1st eq.,
x = 12-4.5 = 7.5

So, the two numbers are 7.5 & 4.5

Hope this helps!

That’d be 9 years or something