Fractions equivalent to 1/4 are 2/8, 3/12, 4/16, 5/20
The constant variation k is 12
The function to the graph is 6
the whole exam will be 100%, and let's say that's "x" questions, but we also know that 9 is 60% of that so

16/21 is your answer
You can take a 2 out of both numbers to get your answer
I hope this helped! :)