There is only one solution
Answer: = (the third option)
Step-by-step explanation
They think this because younger drivers are less experienced.
Answer: I don't know about the formula, but consider the logic below.
Step-by-step explanation:
Martina = 12
Joey = 0
12 x 3 = 36
36 - 3 = 33
If Joey was 21, Martina would be 33.