The strain of bacteria will double in size and then divide every 20 min. Let a, be the initial number of bactería cells, a, the number after 20 min and a, the number after 20(n-1) min. (a) Write a...

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Extracted text: The strain of bacteria will double in size and then divide every 20 min. Let a, be the initial number of bactería cells, a, the number after 20 min and a, the number after 20(n-1) min. (a) Write a formula for the nth terma, of the geometric sequence a1, a2, a3, .., an, ... (b) Determine the first value for n where a,>1,000,000 if a, =500. (c) How long does it take for the number of bacteria to exceed one million?