OGQR 2020: Question No. 208
How old is Jane?
- Ten years ago, she was one-third as old as she is now.
- In 15 years, she will be twice as old as she is now.
| Source | OGQR 2020 |
| Type | Data Sufficiency |
| Topic | Algebra |
| Sub-Topic | Linear Equations |
| Difficulty | Easy |
Solution
Steps 1 & 2: Understand Question and Draw Inferences
We need to find the age of Jane.
- Let us assume that the present age of Jane is x years.
- Hence, we need to find the value of x.
As we do not have any relevant information to infer from, let us now analyse the individual statements.
Step 3: Analyse Statement 1
“Ten years ago, she was one-third as old as she is now.”
- Age of Jane ten years ago = 1/3 (Present age of Jane)
- Ten years ago, the age of Jane was = x – 10 years.
Hence, x – 10 = x/3
- 3x – 30 = x
- From this equation, we can easily find the value of x.
Thus, statement 1 is sufficient to answer the question.
Step 4: Analyse Statement 2
“In 15 years, she will be twice as old as she is now.”
- Age of Jane 15 years after Now = 2 × Present age of Jane
- After 15 years, age of Jane will be = x + 15
- x + 15 = 2x
- From this equation, we can easily find the value of x.
Thus, statement 2 is sufficient to answer the question.
Step 5: Combine Both Statements Together (If Needed)
Since we could determine the answer from either of the statements individually, this step is not required.
Hence, the correct answer is option D.
