document.write( "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?
\n" ); document.write( " A. $1.70
\n" ); document.write( "B. $4.20
\n" ); document.write( "C. $3.35
\n" ); document.write( "D. $3.60
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #304171 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"k\" = the number of \"50\" cent increases in price
\n" ); document.write( "Let \"R\" = revenue
\n" ); document.write( "given:
\n" ); document.write( "\"+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+\" (in cents)
\n" ); document.write( "--------------------------------
\n" ); document.write( "\"+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+\"
\n" ); document.write( "\"+R+=+10500000+-+1250000k+%2B+2100000k+-+250000k%5E2+\"
\n" ); document.write( "\"+R+=+-25k%5E2+%2B+85k+%2B+1050+\"
\n" ); document.write( "\"+R+=+-5k%5E2+%2B+17k+%2B+210+\"
\n" ); document.write( "This is a parabola with a maximum, since the
\n" ); document.write( "coefficient of \"k%5E2\" is minus.
\n" ); document.write( "The max is at \"+-b%2F%282a%29+\" where
\n" ); document.write( "\"a+=+-5\"
\n" ); document.write( "\"b+=+17\"
\n" ); document.write( "\"+-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,
\n" ); document.write( "\"+50%2A1.7+=+85+\" cents is the increase over $2.50 that
\n" ); document.write( "Steve should allow
\n" ); document.write( "\"+2.5+%2B+.85+=+3.35+\"
\n" ); document.write( "He should charge $3.35 per hot dog
\n" ); document.write( "------------------------------
\n" ); document.write( "You can check this by putting \"334\", \"335\" and
\n" ); document.write( "\"336\" into
\n" ); document.write( "\"+R+=++%2842000+-+5000k%29%2A%28250+%2B+50k%29+\"
\n" ); document.write( "and seeing ir \"R\" peaks at \"335\"
\n" ); document.write( "
\n" );