Math problem: How & Why?

Question

What would be your answer to this Math problem and how did you arrive at your answer? My answer is 7 1/2, Agree or disagree?

A dancer practices 28 hours in one week (5 days). Each day she practices one hour more than the day before. How many hours did she practice on Friday?

Answer 1

7.6 or 7 hours 10 minutes

x + (x+1) + (x+2) + (x+3) + (x+4) =

5x + 10 = 28

5x = 18

x = 3.6

(x+4) = 7.6

Answer 2

7.6