Answer:
N - 4 = 3(M - 4). Simplified further, N - 4 = 3(M - 4)
Step-by-step explanation:
Given,
Nina is N years old now and;
Maryna is M years old now
If four years ago, Nina was three times as old as Maryna was, then
Four years ago, Nina's age was N - 4
Four years ago, Maryna's age was M - 4
Given that Nina was three times as old as Maryna was four years ago, it means that
N - 4 = 3(M - 4)
To solve further
N = 3m - 12 + 4
N = 3M - 8