Well, I dont think that amount of money is a real amount so.
But my guess would be $8.60
Explanation:
Since you provided us with 5,9, and 7, you should use the 7 to round up the next number. So, you round the 9, to 10, so you add the 1 from the 10, on the 5. So it is 6. So your answer is $8.60.
