Question

Maggie's brother is 6 years younger than four times her age. The sum of their ages is 69.

How old is Maggie?

Answer 1

Answer: Maggie is 15 years old

Explanation:

69 = (4m - 6) + m --- get an equation

69 - m = 4m - 6 --- lets subtract m from both sides first

75 - m = 4m --- add 6 on both sides

75 = 5m --- add m on both sides

15 = m --- divide by 5 on both sides

m = 15, so Maggie is 15 years old

Let's check:

69 = (4(15)-6) +15

69 = (60 - 6) + 15

69 = 54 + 15

69 = 69

Answer 2

15

Explanation:

If Maggies age is, for example, x, we can say that her brothers age is 4x-6. We know from the problem that Maggies age (x) plus her bothers age, (4x-6) is 69. So,

4x-6+x=69

5x-6=69

5x=75

x=15

So, Maggie is 15.