請教數學題

斗斗=11 years old

Daddy=44 years old

3 years ago= 斗斗:8 years old
Daddy:41 years old

8+41= 49

4y-3+y-3=49
5y-6=49
5y=55
y=11
∴斗斗的歲數是11歲

Let y years old be the age of 斗斗 now.
4y-3+y-3=49
5y-6=49
5y=55
y=11
∴The age of 斗斗now is11 years old.