To solve this problem, let's define the present age of the son as "x."
According to the given information, the father is currently 30 years older than the son. So, the present age of the father can be expressed as "x + 30."
After 5 years, the son's age will be "x + 5," and the father's age will be "x + 30 + 5," which simplifies to "x + 35."
According to the second part of the problem, the father's age will be three times the son's age after 5 years. So, we can write the equation:
x + 35 = 3(x + 5)
Expanding the equation, we get:
x + 35 = 3x + 15
Now, we can solve for x:
2x = 20
x = 10
Therefore, the son's present age is 10 years.
To find the father's present age, we substitute the value of x into the expression "x + 30":
10 + 30 = 40
So, the father's present age is 40 years.
Therefore, the correct answer is B) 40.