Answer:
x=5
Step-by-step explanation:
Let's assign the number of years until Leo will be 3 times as old as Amira as x.
Leo = 19, Amira = Leo-16=19-16=3.
In x number of years, Leo+x = (Amira+x)*3, so 19+x=(3+x)*3. We will then try to isolate x. Subtracting both sides by x and then dividing both sides by 3, we get
19/3 = 3 +x - x/3. Subtracting 3 from both sides, we get 10/3=2*x/3. Multiplying both sides by 3 and then dividing both sides by 4, we get x=5 years