Maggie's brother is 6 years younger than four times her age. The sum of their ages is 39. How old is Maggie?

We can set Maggie's age to x

If her brother is six years younger than four times her age, than her brother must be equal to: 4x-6

Since the sum of their ages is 39, we can set up an equation.

(Sum of Maggie's age) + (sum of Maggie's brother's age) = 39

x + (4x - 6) = 39

5x - 6 = 39

5x = 45

x = 9, Maggie's age is 9