Answer:
Mehmut is 8 years old.
Step-by-step explanation:
From the statement we can get the following information, let M be Mehmut's age and b brother's age:
M = 4 * b
M + 1 = 3 * (b + 1)
We replace the first equation in the second and we are left with:
4 * b + 1 = 3 * b + 3
4 * b - 3 * b = 3 - 1
b = 2
Now, we replace to calculate M:
M = 4 * b
M = 4 * 2
M = 8
Mehmut is 8 years old.