document.write( "Question 136224: A youth group decide to go bowling. You can rent the number of lanes that you need for $100. The cost per person will drop by $0.50 if they can get ten more people to attend. How many people were in the original group? (Please solve in algebra from?) \n" ); document.write( "
Algebra.Com's Answer #99768 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
A youth group decide to go bowling. You can rent the number of lanes that you need for $100. The cost per person will drop by $0.50 if they can get ten more people to attend. How many people were in the original group?
\n" ); document.write( "------------------
\n" ); document.write( "Let number in original group be \"x\".
\n" ); document.write( "Average cost for each was 100/x dollars.
\n" ); document.write( "-----------------------
\n" ); document.write( "After adding 10 people average cost is 100/(x+10) dollars
\n" ); document.write( "------------------------
\n" ); document.write( "EQUATION:
\n" ); document.write( "old average - new average = (1/2) dollar
\n" ); document.write( "100/x - 100/(x+10) = 1/2
\n" ); document.write( "Multiply thru by 2x(x+10) to get:
\n" ); document.write( "200(x+10) - 200x = x(x+10)
\n" ); document.write( "200 = x^2+10x
\n" ); document.write( "x^2+10x-200 = 0
\n" ); document.write( "(x+20)(x-10) = 0
\n" ); document.write( "Positive answer:
\n" ); document.write( "x = 10 (# of people in the original group)
\n" ); document.write( "=====================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
\n" );