Hi! each question below has an answer (Bold). Could you please explain to me why those are the answers and why the others (each) are wrong? I am preparing for my final and just want to make sure I really understand why and why not of each of them. Thanks.

9) Dinkins Inc. is considering disposing of a machine with a book value of $50,000 and an estimated remaining life of five years. The old machine can be sold for $15,000. A new machine with a purchase price of $150,000 is being considered as a replacement. It will have a useful life of five years and no residual value. It is estimated that variable manufacturing costs will be reduced from $70,000 to $45,000 if the new machine is purchased. The net differential increase or decrease in cost for the entire five years for the new equipment is. *a) $10,000 increase b) $25,000 decrease c) $10,000 decrease d) $25,000 increase 10) A business received an offer from an exporter for 10,000 units of product at $13.50 per unit. The acceptance of the offer will not affect normal production or domestic sales prices. The following data are available: Domestic unit sales price $21 Unit manufacturing costs: Variable Fixed What is the amount of the gain or loss from acceptance of the offer? a) $75,000 loss b) $40,000 gain *c) $15,000 gain d) $85,000 gain