Answer:
45% probability that a randomly selected customer saw the advertisement on the internet or on television
Step-by-step explanation:
We solve this problem building the Venn's diagram of these probabilities.
I am going to say that:
A is the probability that a customer saw the advertisement on the internet.
B is the probability that a customer saw the advertisement on television.
We have that:

In which a is the probability that a customer saw the advertisement on the internet but not on television and
is the probability that the customers saw the advertisement in both the internet and on television.
By the same logic, we have that:

12% saw it on both the internet and on television.
This means that 
20% saw it on television
This means that 
37% of customers saw the advertisement on the internet
This means that 
What is the probability that a randomly selected customer saw the advertisement on the internet or on television

45% probability that a randomly selected customer saw the advertisement on the internet or on television
The answer is C to the question
There is no solutions to these linear equations. in order to find how many solutions there are, you first need to solve for the first variable in one of the equations, then substitute the result into the other equation. since both equations are almost the same and the same format, it won't have any solutions.
hope this helped, God bless!