Harmon's sells an average of 40 tubes of chapstick weekly. the normal price paid by Harmon’s is $1 per tube. it costs Harmon $25 to place an order, and Harmon's annual holding cost rate is 20%. answer the following questions:

1). how many tubes of chapstick should be ordered to minimize combined ordering and holding costs?

2). the supplier is willing to offer a 8% discount on orders of at least 800 tubes. how many tubes of chapstick should be ordered to minimize combined ordering, holding and purchasing cost?