Question: The average age of two boys and their father is greater than the average age of those two boys and their mother by 3 yr. The average age of the four is 19 yr. If the average age of the two boys be $ 5\frac{1}{2}yr, $ then find the age of the father and the mother.
Options:
A) 37 yr and 28 yr
B) 47 yr and 38 yr
C) 50 yr and 41 yr
D) 35 yr and 32 yr
Show Answer
Answer:
Correct Answer: A
Solution:
- Let the age of father and mother be x yr and y yr, respectively.
Total age of the four members $ =19\times 4=76yr $
Total age of two boys $ =\frac{11}{2}\times 2=11yr $
According to the question,
$ \frac{11+x}{3}=\frac{11+y}{3}+3 $
$ \Rightarrow $ $ 11+x=11+y+9 $
$ \Rightarrow $ $ x-y=9 $
(i)
$ \Rightarrow $ $ x+y+11=76 $
$ \Rightarrow $ $ x+y=76-11 $
$ \Rightarrow $ $ x+y=65 $
(ii)
On solving Eqs. (i) and (ii), we get
$ x=37yr $ and $ y=28yr $