You do not hyphenate 30 minutes, as in "She took thirty minutes to finish her test."
You do, however, hyphenate 30-minute as in, "She took the thirty-minute exam."
The distinction is that in this latter case 'thirty-minute' is used as a compound adjective (describing the timed exam) whereas in the first example 'thirty' is an adjective describing 'minutes'.
An easier way to remember it is that you only hyphenate when the adjectives are acting together for a single purpose (such as modifying a single word together).
30 minutes = 1/2 hour
0.50 of an hour is 30 minutes.
30 minutes = 1,800 seconds
8:30 minus 60 minutes is 7:30 830 minutes minus 60 minutes is 770 minutes.
There are (30 + 1440k) minutes, where k is an integer.
No.
No - "Each half is 60 minutes." However, you would hyphenate in a sentence such as, "The game consists of 60-minute halves."
You do not need to hyphenate.
You do not hyphenate the number.
Don't hyphenate; ongoing is one word.
You hyphenate it only at the hyphen.
I think it's more accepted to hyphenate it.
7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.7 minutes and 30 seconds.
Can you, or should you? You can hyphenate it if you're moving between lines in a paragraph and need to break up the word. You shouldn't hyphenate it normally.
You would hyphenate "thank you" when it is used as an adjective before a noun, such as in "a thank-you card."
30 minutes
You mean at the end of a line? Well it depends on how much room you have hyphenate at a syllable is probably best. If you have little space before the end of the line don't hyphenate a word. You could hyphenate like this trans- portation.