Aptitude - Problems on Ages - Discussion
Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.
What is the present age of Tanya? | |
I. | The ratio between the present ages of Tanya and her brother Rahul is 3 : 4 respectively. |
II. | After 5 years the ratio between the ages of Tanya and Rahul will be 4 : 5. |
III. | Rahul is 5 years older than Tanya. |
I. Let the present ages of Tanya and Rahul be 3x years and 4x years.
II. After 5 years, (Tanya's age) : (Rahul's age) = 4 : 5.
III. (Rahul's age) = (Tanya's age) + 5.
| From I and II, we get | 3x + 5 | = | 4 | . This gives x. |
| 4x + 5 | 5 |
Tanya's age = 3x can be found. Thus, I and II give the answer.
From I and III, we get 4x = 3x + 5. This gives x.
Tanya's age = 3x can be found. Thus, I and III give the answer.
From III : Let Tanya's present age be t years.
Then Rahul's present age = (t + 5) years.
| Thus, from II and III, we get : | t | = | 4 | . This gives t. |
| t + 5 | 5 |
Thus, II and III give the answer.
Correct answer is (E).
Let me explain;
Equation 1 and 2 & 2 and 3 will give the future after 5 years age.
i.e tania :20 year and rahul : 25 , because both consist equation 2 (which says after 5 years )
Whereas equation 1 will give the present age,
i,e. tania :15 , rahul : 20.
Hope you all get it , good day.