If Anika is 30 now, in 15 years, she'll be 30+15=<<30+15=45>>45 years old.
At 30, Anika is 4/3 the age of Maddie, meaning Maddie is 4/3*30=<<4/3*30=40>>40 years.
In 15 years, Maddie will be 40+15=<<40+15=55>>55 years old.
Their total age in 15 years will be 55+45=<<55+45=100>>100
Their average age in 15 years will be 100/2=<<100/2=50>>50
#### 50