一個產經的題目 - 經濟

題目如下：Norman International has a monopoly in the manufacture of

whatsits. Each whatsit requires exactly one richet as an input

and incurs other variable costs of $5 per unit. Richets are made

by Rich Inc., which is also a monopoly. The variable costs of

manufacturing richets are $5 per unit. Assume that the inverse

demand for whatsits is Pw=50-Qw , where Pw is the price of

whatsits in dollars per unit and Qw is the quantity of

whatsits offered for sale by Norman International.

Assume the two firms expect to last forever and that the discount

factor R is 0.9. What is the maximum amount that Rich would be

willing to pay the owners of Norman International to take over

Norman ?(hint：calculate the present value of the profits of the

two firms before and after the merge.)

我已經算出來合併前的利潤，Norman=100 Rich=200 合併後＝400

但discount factor那一段實在是怎麼樣都看不懂，

麻煩大家幫我解惑一下，非常感謝！！


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