a man is now three times as old as his son and was 30 when his son was born. how old is his son now?
15
60 years old
To find the age of the son, we need to find the current age of the man and then calculate.
Let's start by assigning variables to the unknowns:
Let M be the current age of the man.
Let S be the current age of the son.
From the given information, we know that the man is currently three times as old as his son, which can be expressed as:
M = 3S --- equation (1)
We are also given that when the man was 30, his son was born. This indicates a time difference of 30 years between their ages. So, we can express this information as:
M - 30 = S --- equation (2)
Now, we have a system of two equations with two variables (M and S). We can solve this system using substitution or elimination method.
From equation (1), we have M = 3S. We can substitute this value for M in equation (2):
3S - 30 = S (since M = 3S is substituted in place of M)
Simplifying the equation, we have:
2S = 30
To find the value of S (the son's current age), divide both sides of the equation by 2:
S = 15
Therefore, the son is currently 15 years old.