Since I was asked the age by niece, I answered as follows.
"My age now is five years younger than your mother and after five years my age will be five times of your present age and your mother's age will be three times of your age at that time."
How old am I now ?
"My age now is five years younger than your mother and after five years my age will be five times of your present age and your mother's age will be three times of your age at that time."
How old am I now ?
Answer
The age of mother of the niece five years later is ⑤+5 years old which is three times of niece age which is ①+5.
This relation can be expressed with a formula as (①+5) × 3 = ⑤+ 5.
From this expression, it becomes ③ + 15 = ⑤ + 5 and is identified as ① = 5 years old.
Because my present age is ⑤ -5 years old which comes to 5 × 5 - 5 = 20 years old.
20 years old
Solution
When assume the present age of the niece ① years old, my age five years later is ⑤ years old.
The age of mother of the niece five years later is ⑤+5 years old which is three times of niece age which is ①+5.
This relation can be expressed with a formula as (①+5) × 3 = ⑤+ 5.
From this expression, it becomes ③ + 15 = ⑤ + 5 and is identified as ① = 5 years old.
Because my present age is ⑤ -5 years old which comes to 5 × 5 - 5 = 20 years old.
(Schoolchildren sometimes use such method similar to equation in case it is easier than other method.)
