Guess the age of Mayra from the following conversations?

Question

Fresh and invigorated after completing her algebra homework, Mayra appeared at the living room door. She held a piece of paper covered in scribbled numbers, 'm's, 'd's, and equations.

"Dad!" she announced. "Five years from now you'll be only double my age!"

"Amazing!" Dad almost looked up from the TV, but knew she hadn't finished.

"But five years ago, you were triple my age then!"

"I suppose," Dad grunted, changing channels.

How old is Mayra?

Answer 1

Let 5 years ago the age of the daughter be x
then
(3x) - (x) = 2x => (difference of their age five years ago) --------------- 1

5 years into the future

2*(x+10) - (x+10) = x + 10 ------------------- 2

Since difference in their ages won't change with time
1=2

x + 10 = 2x
x = 10 years was the daughter's age 5 years ago
So at present it should be x + 5 = 15 years.