If one person is 3 times the age of a second person and in 18 years the first person is twice the second person's age, how old are the two people?
Let's denote the ages of the two people as person 1 (P1) and person 2 (P2).
Given:
P1 = 3P2
After 18 years:
P1 + 18 = 2(P2 + 18)
Substitute P1 = 3P2 into the second equation:
3P2 + 18 = 2(P2 + 18)
3P2 + 18 = 2P2 + 36
3P2 - 2P2 = 36 - 18
P2 = 18
Now substitute P2 = 18 into the first equation:
P1 = 3(18)
P1 = 54
Therefore, the first person is 54 years old and the second person is 18 years old.