I keep looking and looking at this.
Double checking the capitalisation. Making sure I'm not mixing bits and bytes. Double checking the words. Double checking the sentence. Wondering if there is a reason for the embolden text. Thinking what am I missing?
Logic tells me 80Mb - 20Mb = 60Mb
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But just to make sure, lets try the long way:
1 Megabit = 1,000,000 bits
20Mb = 20,000,000 bits
80Mb = 80,000,000 bits
80,000,000 - 20,000,000 = 60,000,000
60,000,000 bits = 60Mb