Well, it asks that you evaluate 24 for y.
Also, notice that it says "the difference of a number and 6"
So your equation should have been
y - 6
And after evaluating
24 - 6
Then solve
24 - 6 = 18
18 should have been the answer
So no, the student's work is not correct, because the student wrote a division expression instead of a subtraction equation