How many minutes are there from 3pm to 7.30pm?

Oh, dude, let me grab my calculator... just kidding. So, from 3pm to 4pm, that's one hour. Then from 4pm to 7pm, that's three hours. And finally, from 7pm to 7:30pm, that's half an hour. Add them up, and you get 4.5 hours, which is like 270 minutes. Easy peasy!