Difficulty: Easy
Correct Answer: 3 years
Explanation:
Introduction / Context:
This problem combines proportional age growth over 9 years for a mother with a present age ratio between the mother and her daughter. Once Ishikha's present age is determined, the daughter's age can be obtained easily and then adjusted to find her age 3 years ago. The problem nicely mixes fractions and time shifts.
Given Data / Assumptions:
Concept / Approach:
Let I be Ishikha's present age. Her age at marriage was I - 9. The relation tells us I = (4/3) * (I - 9). We solve this equation to find I. Then the daughter's current age is I / 6. Subtracting 3 years from that gives the daughter's age three years ago. The steps use proportion and simple linear equations.
Step-by-Step Solution:
Let Ishikha's present age be I years.
Her age at marriage, 9 years ago, was I - 9 years.
The condition says I = (4/3) * (I - 9).
Multiply both sides by 3: 3I = 4(I - 9).
So 3I = 4I - 36 which simplifies to -I = -36.
Hence I = 36 years.
Her daughter's present age is one sixth of 36, so daughter's age now = 36 / 6 = 6 years.
Three years ago, daughter's age = 6 - 3 = 3 years.
Verification / Alternative check:
At marriage, Ishikha was 36 - 9 = 27 years old. Four third of 27 is (4/3) * 27 = 36, which matches her present age. The daughter being 6 years old now is indeed one sixth of 36. Three years ago, she would have been 3 years old. All conditions are satisfied, so the result is consistent.
Why Other Options Are Wrong:
A daughter aged 4 or 5 years three years ago would be 7 or 8 now, which is not one sixth of 36. Values like 1 or 2 years three years ago would make her present age 4 or 5 years, which again does not match the one sixth proportion. Only 3 years ago leads to a present age of 6, maintaining the exact ratio with Ishikha's age.
Common Pitfalls:
Mistakes often come from misinterpreting the phrase four third and writing the equation incorrectly as (3/4) instead of 4/3. Other errors include forgetting to subtract 9 to obtain the marriage age or mixing up whether to divide or multiply when using one sixth. Keeping clear symbols and carefully translating each condition minimizes such issues.
Final Answer:
Therefore, Ishikha's daughter was 3 years old three years ago.
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