document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=892773>Question 892773</A>: <I><SPAN STYLE=\"word-break: break-all;\"> There are 50 total ducks and cows in a field. 154 total legs can be counted. How many cows are there? How many ducks? \r<BR>\n" );
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document.write( "I am going into 7th grade and not sure how to solve this.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #540776 by </B><A HREF=/tutors/aboutme.mpl?userid=LinnW><B>LinnW(1048)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=LinnW><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=LinnW><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=540776\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let d = the number of ducks<BR>\n" );
document.write( " c = the number of cows<BR>\n" );
document.write( "( the number of ducks ) times ( 2 legs per duck )<BR>\n" );
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document.write( "( the number of cows ) times ( 4 legs per cow ) = 154<BR>\n" );
document.write( "d*2 + c*4 = 154<BR>\n" );
document.write( "We also know that the number of ducks plus the number of cows = 50<BR>\n" );
document.write( "d + c = 50<BR>\n" );
document.write( "We have two equations<BR>\n" );
document.write( "d + c = 50 and d*2 + c*4 = 154. Let's rewrite the second equation<BR>\n" );
document.write( "2d + 4c = 154<BR>\n" );
document.write( "Using d + c = 50 let's solve for d<BR>\n" );
document.write( "d + c = 50<BR>\n" );
document.write( " add -c to each side<BR>\n" );
document.write( " d = 50 -c<BR>\n" );
document.write( "Substitute (50 - c) for d in 2d + 4c = 154<BR>\n" );
document.write( "2(50 - c) + 4c = 154<BR>\n" );
document.write( "100 -2c + 4c = 154<BR>\n" );
document.write( "100 + 2c = 154<BR>\n" );
document.write( "add -100 to each side<BR>\n" );
document.write( " 2c = 54<BR>\n" );
document.write( "divide each side by 2<BR>\n" );
document.write( " c = 27<BR>\n" );
document.write( "Since d = 50 - c<BR>\n" );
document.write( "d = 50 - 27 = 23<BR>\n" );
document.write( "So we have 27 cows and 23 ducks<BR>\n" );
document.write( "27(4 legs) + 23( 2 legs )<BR>\n" );
document.write( "108 + 46 = 154 legs in total<BR>\n" );
document.write( "27 cows and 23 ducks = 50 animals in the field<BR>\n" );
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