how do i subtract date and time into hours and convert hours to decimal in excel

[LesPink]

I am trying to subtract cells that contain a date and time from another cell that contain a date and time into hours and then convert that to a decimal. E.g. 18/10/2018 4:53:50 AM minus 17/10/2018 5:12:30 PM equals (hours as a decimal number). Anyone any ideas how I can reliably do this? Thanks in advance.

[#2]

@LesPink 

That's 

=(C3-B3)*24

In Excel 1 Hour is equal to 1/24.

[#3]

@Sergei Baklan 

Thanks Sergei. I tried that and it didnt seem to be working, but you are correct. Appreciate you taking the time to help. Les

[#4]

@LesPink , did you check the file I attached to previous post?