Could you be any less helpful?

I could try.

An idea on how to do that

You have hour as an integer, so storing 1.25 in that is not going to work. You want some resolution on time that is less than 1 hour. You need to define what that resolution is. If it is 1/4 hour, then you need to keep track of minutes, not hours. When you need to know how much time has elapsed, you divide minutes by 60 to get hours. You then subtract 60 times the number of hours to get the remainder. Multiply that value by 4 to get quarter hours.

If the time that you have measured is 78 minutes, that's 1 hour and 18 minutes, or 1 hour, 1 quarter hour and 3 minutes. Ignore the minutes. You can decide to round or truncate as you see fit. You might want 85 minutes to be 1 hour and 1 quarter hour or 1 hour and 2 quarter hours.

Oops, that was not being less helpful. I'll try harder in the future.

even a suggestion on some other improvement would have been more appropriate.

You asked a specific question. "Can I do this?" I answered that question. You did not ask how to do it, or for a review of the code, so I didn't answer those unasked questions.