Calculations with Times

(I've sent this yesterday but it seems to not have been posted.)

In MS Access, I need to calculate % of Estimated Time to Actual Time.

Estimated Time is calculated in a Query as Quantity/RatePerHour so I end up with a decimal format figure, e.g., 100000/15000 = 6.66667 (hours) which incorrectly displays as 16:00 (hh:mm) in my report (problem 1) .

The Actual Time is calculated in the Query by subtracting the start date & start time from the end date & end time, i.e., (Edate&Etime)-(Sdate&Stime) and this gives me a "Short Time" format result, e.g., 0.270833333335759 which displays as 6:30 (hh:mm) in my report.

When I divide Estimated Time by Actual Time, I get a weird 304%. It should be 97.4%. (problem 2)

Any ideas on how I should process to get correct %?
Many thanks
Michael