Question

Mary is 3 years older than her brother. Her brother is half as old as their mom. The sum of all three of their age is 63. How old is mary?

Answer 1

Since Mary is 3 years older than her brother, and her brother is half as old as their mom, and the sum of all three of their ages is 63.. You just do this..
You divide 60 by 4 and then that gets you to 15.
You then add 3 onto Mary's brothers' age to get to 18.
So Mary is 18.

Answer 2

Mary is 18. Hope it helps!