A Rhode Island company produces communion wafers for churches around the country and the world. The little company produces a lot of wafers, several hundred million per year. When in production, the process produces wafers at the rate of 40 per second. During this production process the wafers must spend 4 minutes in an oven and then 8 minutes passing through a cooling tunnel. This company can produce wafers each minute. On average, when in production there are in total 28800 wafers in the oven and the cooling tunnel. If the wafers are packaged in cases, each holds 1200 wafers, then this company can produce cases of wafers each hour. If the demand for wafers is 2400 cases per day, then the company needs to be in production for hours each day in order to satisfy such demand. Under the same demand, if the company warehouse holds 3600 cases of wafers, then each case of wafers stays in the warehouse for days on average before shipping.

Required:
How many wafers does the cooling tube hold on average when in production (in other words, don't count the time they are not in production)?