Please help me solve this homework problem and show steps to complete.

Dan Bumblauskas is the owner of a small lowa company that produces electric knives used to cut fabric. The annual demand is for 8,000 knives, and Dan produces the knives in batches. On average, Dan can produce 140 knives per day; during the production process, demand has been about 90 knives per day. The cost to set up the production process is $100, and it costs Dan $1.20 to carry a knife for 1 year. How many knives should Dan produce in each batch? Dan should produce knives in each batch (round your response to the nearest whole number)