In a certain font, a monochrome laser printer can print 50 lines of 80 characters per page. The average character occupies a box 2 mm x 2 mm, about 25% of which is toner. The rest is blank. The toner layer is 25 microns thick. The printer's toner cartridge measures 25 x 8 x 2 cm. How many pages is one toner cartridge good for