Answer:
First of all this question makes no complate sense if this was in real life. But the answer is: Allen is 23 years old and Jim woukd be 12 1/2 years old.
Explanation:
Because 20+3=23. That's because it said in 3 years. Tthen we divide by 2 to find Jim's age. That's because it said that in three years, Allen would be twice as old as Jim.