If a printer can print 12 pages in 9 seconds, you can calculate the number of pages it can print in one minute (60 seconds) by setting up a proportion:
12 pages / 9 seconds = x pages / 60 seconds
Cross-multiplying gives you:
9x = 12 * 60
Solving for x:
x = (12 * 60) / 9
x = 80
So, the closest estimate of the number of pages the printer can print in one minute is 80 pages.