SOLUTION: Steve owns a hotdog stand. He has found that sales of hot dogs average 42,000 hot dogs a year when the hot dogs sell for $2.50 each. For each 50 cent increase in the price, the num

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Question 440190: Steve owns a hotdog stand. He has found that sales of hot dogs average 42,000 hot dogs a year when the hot dogs sell for $2.50 each. For each 50 cent increase in the price, the number of hotdogs sold drop by 5000. What price per hot dog should Steve charge to realize the maximum revenue?
A. $1.70
B. $4.20
C. $3.35
D. $3.60

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let k = the number of 50 cent increases in price
Let R = revenue
given:
+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+ (in cents)
--------------------------------
+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+
+R+=+10500000+-+1250000k+%2B+2100000k+-+250000k%5E2+
+R+=+-25k%5E2+%2B+85k+%2B+1050+
+R+=+-5k%5E2+%2B+17k+%2B+210+
This is a parabola with a maximum, since the
coefficient of k%5E2 is minus.
The max is at +-b%2F%282a%29+ where
a+=+-5
b+=+17
+-b%2F%282a%29+=+-17%2F%28-10%29+=+1.7%0D%0ASince+%7B%7B%7Bk is the number of 50 cent increases in price,
+50%2A1.7+=+85+ cents is the increase over $2.50 that
Steve should allow
+2.5+%2B+.85+=+3.35+
He should charge $3.35 per hot dog
------------------------------
You can check this by putting 334, 335 and
336 into
+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+
and seeing ir R peaks at 335