Mary is 15 years older than her niece Katie. In 10 years Mary is two times as old as Katie. How old are Mary and Katie now?

How do I solve this (equation + work)
Thank you!

1 answer

Katie's age -- x
Mary's age -- x+15

10 years from now:
Katie : x+10
Mary : x+15 + 10 = x + 25

"Mary is two times as old as Katie" ---> 2x+25 = 2(x+10)

should be easy to solve