Question

The age of a girl in months is equal to the age of her grandmother in years. If the difference between their ages is $66$ years, find their ages.

• A. The age of girl is $5$ years and that of grandmother is $60$ years
• B. The age of girl is $6$ years and that of grandmother is $72$ years
• C. The age of girl is $7$ years and that of grandmother is $84$ years
• D. The age of girl is $8$ years and that of grandmother is $96$ years

Answer 1

Answer: (B)

The age of girl is $6$ years and that of grandmother is $72$ years

Let the age of grandmother is $12x$ years.

Then, the age of girl $=$ $\frac{12x}{12}=x$ years
According to the given condition,
$12x-x=66$
$\Rightarrow 11x=66$

$\Rightarrow x=6$
Therefore, the age of girl $=6$ years and that of grandmother $=12\times 6=72$ years.