Can you answer these 2 questions? thx

In a school 2/3 of the students study a language of those who study a language 2/5 study french

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

What is a graph with a never ending line called?