cs3265 midterm exam part 1

there are some queries i had for the midterm paper
but after dr.Chen explain
i suddenly feel that i should had studied the answers she gave
Below is the email i wrote to her -- for question number 1
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Dear Dr.Chen
Regarding the midterm paper, I do have a query in calculations.
Question 20.

Customer Type	PhotoKing	Individual pricing		VideoKing	Individual pricing
		No. of customers WTP	total		No. of customers WTP	total
A	$70	300	$21,000	$80	200	$16,000
B	$80	200	$16,000	$50	400	$20,000
C	$30	400	$12,000	$90	100	$9,000
D	$100	100	$10,000	$70	300	$21,000

So, from this we can deduce that both individual pricing should be $70.

The bundle pricing in this case have to be lower than $140. ($70 + $70)

Therefore taking the bundle pricing: $130

Type A, B & D customers would purchase

130 x 300 = 39,000

Type C customers would purchase only video king at $70

70 x 100 = $7,000

Total = $39,000 + $7,000 = $46,000

$120

All type of customers would purchase

120 x 400 = $48,000

Therefore if the firm sells both bundle and individual items, the price for the bundle to obtain maximum profit is $120.

Whereas the answer given by you is $130 instead, I wonder if there are errors in this calculations.
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okay, if what i said seems correct... then you are WRONG

her reply is below
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When the bundle is $130, only Type C consumers will purchase individual items at $30 for PhotoKing and $90 for VideoKing. The total revenue from individual item selling is $30x100+$90x100=$12000. Add this amount to the bundling selling revenue, total revenue =$39000+$12000=$51000.

The seller will not sell individual items at $70 to Type C consumers if they can get higher revenue.

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tada, sounds correct, i although i had weird feeling about the individual pricing...
but it is convincing in the end.