don't use excel or solver.... explain how to do it by hand

ToFrom Trucking serves two segments of customers. One segment (A) is willing to pay $3.50 per cubic foot but wants to commit to a shipment with only 24 hours' notice. The other segment (B) is willing to pay only $2.00 per cubic foot and is willing to commit to a shipment with up to one week's notice. With two weeks to go, demand for segment A is forecast to be normally dis- tributed, with a mean of 3,000 cubic feet and a standard deviation of 1,000. How much of the available capacity should be reserved for segment A? How should ToFrom change its decision if segment A is willing to pay $5 per cubic foot