Answer: The required age of Nate is 4 years.
Step-by-step explanation: Given that Alice is 3 years old and Nate is half of the sum of Alice's age and 5.
We are to find the age of Nate.
Let x and y represents the ages of Alice and Nate respectively in years.
Then, according to the given information, we have

and also,

Thus, the required age of Nate is 4 years.