A Question is given followed by two Statements I and II. Consider the Question and the Statements.
Age of each of P and Q is less than 100 years but more than 10 years. If you interchange the digits of the age of P, the number represents the age of Q.
Question: What is the difference of their ages?
Statement-I : The age of P is greater than the age of Q.
Statement-II: The sum of their ages is times their difference.
Which one of the following is correct in respect of the above Question and the Statements?
Correct Answer :
The Question can be answered by using one of the Statements alone, but cannot be answered using the other Statement alone
Solution :
The correct option is: The Question can be answered by using one of the Statements alone, but cannot be answered using the other Statement alone
Let us analyze the problem step-by-step.
We are given that the age of each of P and Q is less than 100 years but more than 10 years. This means both ages are two-digit numbers.
Let the age of P be represented as a two-digit number:
where and are digits from 1 to 9 (since the ages are greater than 10, the tens digit cannot be 0, and because interchanging the digits also gives a two-digit age for Q, the units digit also cannot be 0).
If we interchange the digits of the age of P, we get the age of Q:
Now, let us find the difference between their ages:
Thus, the difference in their ages is always a multiple of 9.
Let us evaluate Statement-I: The age of P is greater than the age of Q.
This statement implies , which means . Therefore:
However, Statement-I alone does not give us the specific values of and or the value of . So, the difference cannot be uniquely determined using Statement-I alone.
Let us evaluate Statement-II: The sum of their ages is times their difference.
The sum of their ages is:
According to Statement-II:
Substituting the expressions for Sum and Difference:
Dividing both sides by 11:
Simplifying the fraction:
Since the left side is positive and symmetric, let us assume without loss of generality that (the difference remains the same whether or ). This gives:
Since and must be single-digit integers from 1 to 9, the only possible integer values that satisfy are:
(Any other positive integer for would make , which is not a single digit).
Thus, the digits must be 5 and 1.
The difference between their ages is:
We obtained a unique value of 36 for the difference using Statement-II alone, without needing Statement-I.
Hence, the Question can be answered by using Statement-II alone, but cannot be answered using Statement-I alone.
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