ANSWER
An exponential growth function.
EXPLANATION
The given function is

This function is of the form,

Since k is positive , the function will grow exponentially and fall asymptote to the negative x-axis.
As x-values becomes bigger and bigger positively, the graph grows exponentially.
The Answer is in the attached file, I'm sorry if I can't write it on laptop, hope this helps man! :) and tell me if it's correct or wrong when your teacher see's it.
500 = 200 + 20h is our equation.
Subtract 200 from both sides
300 = 20h
Divide by 20
300/20 = 15.
It will take 15 hours to get 500 points.
Hope this helps!
This are fractions because they are not mixed fraction by the way those two are 0.5