ans the question
Let the age of daughter be X years.
A mother is 20 years older than her daughter,
Then, the age of mother = ( X + 20) years
4 years before she was 5 times of her daughter’s age at the time,
(X + 20) – 4 = 5 (X – 4)
X + 20 – 4 = 5 X – 20
5 X – X = 16 + 20
4 X = 36
X = 36/4
X = 9
Then, the age of daughter is 9 years.