In 1930, a persons age was 8 times that of his son. In 1938, the fathers age became ten times that of his sons age in 1930. The ages of the son and father in 1940 were, respectively.

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Q: 145 (IAS/2001)
In 1930, a person’s age was 8 times that of his son. In 1938, the father’s age became ten times that of his son’s age in 1930. The ages of the son and father in 1940 were, respectively.

question_subject: 

Maths

question_exam: 

IAS

stats: 

0,10,10,4,4,10,2

keywords: 

{'ages': [0, 0, 3, 2], 'age': [2, 1, 1, 2], 'years': [1, 0, 0, 2], 'times': [5, 2, 7, 3], 'father': [15, 3, 10, 14]}

In this question, we have some mathematical relations for the ages of a father and his son.

In option 1, if the son was 16 years old in 1940, then he would have been 6 in 1930 and the father 48 in 1930. Eight years later, the father would be 56, which is not ten times the son`s age in 1930, so option 1 is incorrect.

Option 2 suggests the son was 15 in 1940, which means he was 5 in 1930 and the father 40. Eight years later, the father would be 48, again not ten times the son`s age in 1930, so option 2 is incorrect.

Option 3, the correct answer, puts the son at 14 in 1940, making him 4 in 1930 and the father 32. Eight years later, the father would be 40, exactly ten times the son`s age in 1930.

Option 4 with the son at 13 in 1940, 3 in 1930, and the father 24, doesn`t fit the equation as eight years later the father is 32 not ten times the son

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