Answer:
The mother is 56 years old while her son is 8 years old
Explanation:
Let x be the age of the mother
Let y be the age of her son
A mother is currently 7 times older than her son
x = 7y -------equation 1
In 4 years time, she will be 5 times older than her son
In 4 years, their ages will be
x + 4 ------mother
y + 4 ------son
x + 4 = 5(y+4)
x + 4 = 5y + 20 ----equation 2
Substitute equation 1 to equation 2
7y + 4 = 5y + 20
Transpose
7y - 5y = 20 - 4
2y = 16
y = 16/2
y = 8
Substitute y = 8 to equation 1
x = 7y
x= 7(8)
x = 56