help creating a formula (maybe a mocros) in excel to calculate break entitlement

Hi there, i am trying to create a new break plan at my work and I need a calculation to tell us what breaks the employee is entitled to during their shift, I currently have a column for their start time, a column for their end time and then 4 columns each representing a different break ( 15 min, 15 min, 30 min and 60 min) and then a total hours column. I basically want a tick or similar to appear in the break columns when the employee is entitled to the break, so if the employee is on a 8 hour shift, they are entitled to 2 15 minute breaks and one 60 minute break, so I want a macro that will result in a tick in both 15 boxes and the 60 box when the start and end times are entered (I have already done the formula to calculate the total hours worked) Can anyone tell me what formula I need to do this?

this thread was accidently duplicated several times (site was telling me it wasn't working and to try again, then it seems when the server was back up and running, it posted several all at once)can't seem to delete the excess ones. there is a attachment on one of the other threads (the only one with more than 1 reply) but I'll attach and explain here too. I basically tried at first to set a conditional formula, so that a tick would appear in the correct boxes when certain criteria are met. The criteria are as follows: a tick in the first 15 box when the TOT HRS column is 4 or more hours, a tick in both 15 boxes and the 30 box when the TOT HRS is 6 hrs or more, a tick to appear in both 15 boxes and the 60 box when the TOT HRS is 8 hrs or more, and a tick in both 15 boxes the 30 and the 60 if the TOT HRS is 10 or more. for some reason the conditional formula wouldn't set in the cell, and my knowledge of excel is limited.

Try

in first 15

=IF($I3>=4/24,"x","")

in second 15

=IF($I3>=6/24,"x","")

in 30

=IF(OR(AND($I3>6/24,$I3<8/24),$I3>=10),"x","")

in 60

=IF($I3>8/24,"x","")