There are 25 coins inside a container. Some of the coins are nickels, and the rest are quarters. The value of the coins is $4.05. Let n represent the number of nickels, and let q represent the number of quarters. Which system of equations represents this situation?

Answer 1

"Which system … ?"

Are there supposed to be choices??

Answer 2

surely the correct choice will look something like
n+q = 25
5n+25q = 405

Answer 3

why though?