Lucy's Fruit Count

Lucy has a basket of oranges and apples. She counts a total of 20 fruits in her basket. If the number of oranges is represented as o and the number of apples as a, she knows that:

$$o + a = 20$$

Additionally, she has 5 more oranges than apples. This can be expressed as:

$$o = a + 5$$

How many apples does Lucy have in her basket?