Answer: Marie is 34 and Joanna is 21.
To find this you first subtract 13 from 55. This will give you 42, which you then divide by 2 to find Joanna's age. Finally you simply add 13 to Joanna's age to find Marie's age (34). To check this, add 34 and 21 together, which gives you 55.
I hope this helps!
