Sagot :
22,400 copies in 7 hours means 22,400/7 copies in 1 hour.
Number of copies in 21 hours is 22,400/7 x 21 = 67,200 copies
Number of copies in 21 hours is 22,400/7 x 21 = 67,200 copies
67,2000 I believe, but I see that you already got an answer so this made no sense but yeah hah