Question

Twenty years ago, my age was $ \dfrac{1}{3}rd$ of what it is now. My present age is
A.25 years
B.30 years
C.33 years
D.42 years

Answer 1

Hint: Reading the question carefully will always help in age-related problems. The ago and after are the main words to look out for in a question. If ages are compared and given in the ratios carefully take the correct values.
In this case age of one person before and after 20 years is compared solve step wise

Complete step-by-step answer:
While solving the problem look for the given data.
Given, twenty years ago the age was $ \dfrac{1}{3}rd$ of present age
Let the present age be x years
The age before 20 years was (x - 20) years
According to given question (x – 20) is $ \dfrac{1}{3}rd$ of present age
Solving the problem,
 \[
  (x - 20) = \dfrac{x}{3} \\
   \Rightarrow 3x - 60 = x \\
   \Rightarrow 2x = 60 \\
   \Rightarrow x = 30\,years \;
 \]
SO, the present age of the person is 30 years.
Hence, option (B) is correct
So, the correct answer is “Option B”.

Note: It is always advised to assume the present age first and then read the conditions given in the question. The age problems can be tricky, sometimes trying to solve them separately in steps. The final answer coming will be the assumed age x. This method can be used in various other problems with only one variable varying.
We can find this solution by trial and error method after finding the age we put it in given condition and check it.