Question

Maggie's brother is 3 years younger than three times her age. The sum of their ages is

21.
How old is Maggie?
Maggie is
years old

Answer 1

21/3 = 7 Maggie is 7 years old

Answer 2

Maggie is 6 years old.

Maggie's brother is 15 years old

Explanation:

Take Maggie's age as 'x'

Her brother's age = 3x - 3

Sum of their ages = 21

Hence,

Maggie's age + brother's age = 21

(x) + ( 3x-3 ) = 21

x + 3x - 3 = 21

4x = 21 + 3

4x = 24

x =
`(24)/(4)`

x= 6

Maggie's age = x = 6

Her brother's age = 3x - 3

= 3(6) -3

= 18 - 3

= 15 years

Hope this helps.