transform hours into minutes

lolo123  that may depend on how that time is stored.  For example if it is text then you may need to parse the text 

=--LEFT(A1,SEARCH(":",A1)-1)*60--MID(A1,SEARCH(":",A1)+1,2)

if it is a number and in excel date-time format then you need to convert it into just mins

=A1*24*60

but that assumes the 'Date' part of the Date-Time is not set therefore 0, which based on your example it is almost certainly true (or it is text).  If you do have date and time information (e.g. 6/5/2020 9:35 am) you would need:

=HOUR(A1)*60 + MINUTE(A1)

finally, note that these results should all be formatted as general or number and not time as these formula convert to a raw count of the number of minutes.