Answer:
Option 3.
Step-by-step explanation:
The given function is
where, x is number of coupon books.
We have to find the practical domain for the given function.
Domain : The set of input values is called domain.
It is given that Raul is selling coupon books. He started with 50 coupon books and has already won a prize for selling at least 10 coupon books.
The number of coupon books can not be a decimal or fraction value. It means the values of x are integers.
The value x is all integers from 10 to 50.
Hence, the correct option is 3.