21 days. If Jean makes 2 per 3 days and you need to know how many she can make in 14 days, then this is what you do. 4 blankets per 6 days, 6 blankets per 9 days, 8 blankets per 12 days, 10 blankets per 15 days, 12 blankets per 18 days, 14 blankets per 21 days. Therefore, 14 blankets per 21 days is your answer! Hope this helps Sierra! :D