Alvin is 30 years old and Simon is 5 years away from being 1/2 the age of Alvin. How old is Simon? Think carefully first, then make a decision:
1 / 2 the age of Alvin who is 30 is 30 / 2 = 15. Simon is 5 years away from being half the age of Alvin so Simon is 15 - 5 = 10 years old. So, the answer is 10.