I believe it is $7.25.
This being because if you start with $21.75 you have to divide that by 3, because you have 3 people splitting the bill.
Another way to do this is by dividing .75 by three (which we know 75 divided by 3 equals 25 so the .75 divided by 3 equals .25. Then we know 21 divided by 3 is 7. So then you would just add 7 + .25 together and get $7.25!
I hope this helped!
