Agatha is five times older than her son bob. three years ago she was nine times older. how old is agatha?

Write an equation system based on the problem
"Agatha is five times older than her son, Bob" could be written as:
  a = 5b(first equation)
"Three years ago, she was nine times older" could be written as:
  a - 3 = 9(b - 3)(second equation)

Solve the equation system
To find the value of b, substitute 5b as a to the second equation
a - 3 = 9(b - 3)
5b - 3 = 9(b - 3)
5b - 3 = 9b - 27
5b - 9b = -27 + 3
-4b = -24
   b = -24/-4
   b = 6
Her son, Bob, is 6 years old

To find Agatha's age, substitute the value of b to the first equation
a = 5b
a = 5 × 6
a = 30
Agatha is 30 years old

Bis your answer. it only holds the decimal numerals