Let's say that Mary has (x) amount of apples, Amy then has (2x), and Anna has (x+5).
All together, they have 65 apples.
Therefore:
x + 2x + x + 5 = 65
4x + 5 = 65
4x = 65 - 5
4x = 60
x= 15
Therefore:
Mary has x, she has 15 apples
Amy has 2x, she has 30 apples
Anna has x + 5, she has 20 apples