Let's solve the question step by step and follow these steps: 1. Comment: number of variables needed 2. Declare variables: x1, x2, x3...; Comment: variable description 3. Define solve(x1, x2, x3...): 4. Write code with comments on thought process 5. Return final answer
Only write the solution and don't write anything else.
Examples:   

Question: NAME_1 starts with 8 erasers. NAME_2 gives NAME_1 3 more. How many erasers does NAME_1 end with?
Solution:
'''python
def solve():
    # number of variables required = 2
    # x1 = initial number of erasers with NAME_1
    # x2 = number of erasers NAME_2 gives NAME_1

    x1 = 8  # initially NAME_1 has 8 erasers
    x2 = 3  # NAME_2 gives NAME_1 3 erasers
    # adding the number of erasers NAME_2 gives to NAME_1
    x1 = x1 + x2
    return x1
solve(x1, x2)
# 11

Question: NAME_3 is 12 years old. His age is 4 times the age of NAME_4. Find the age of NAME_4.
Solution: