document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1145904>Question 1145904</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is a question from my son's test. He got (a) correct but (b)wrong. He doesn't understand why. Would appreciate an explanation that can help him understand his mistake.\r<BR>\n" );
document.write( "\n" );
document.write( "A submarine is at −750 feet or 750 feet below sea level. It descended 300 feet, then ascended 550 feet, and then descended 425 feet.<BR>\n" );
document.write( "a. Write and evaluate a numerical expression to find the submarine’s final elevation. His answer is -925 feet which is correct. \r<BR>\n" );
document.write( "\n" );
document.write( "b. The submarine next descended to the ocean floor, which was at an elevation of −2,250 feet. How far did the submarine descend? <BR>\n" );
document.write( "He answered -1325 feet because according to his understanding the submarine descended so should be negative. However, the correct answer should be 1325 ft (not - 1325 ft). Please help him understand why.\r<BR>\n" );
document.write( "\n" );
document.write( "Greatly appreciate your help, as always.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #767179 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=767179\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> He answered -1325 feet because according to his understanding the submarine descended so should be negative. However, the correct answer should be 1325 ft (not - 1325 ft). Please help him understand why.<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "It's semantics.<BR>\n" );
document.write( "It descended 1325.<BR>\n" );
document.write( "Descent assumes negative.<BR>\n" );
document.write( "It ascended -1325 feet.<BR>\n" );
document.write( "=========<BR>\n" );
document.write( "consider a \"round trip.\"<BR>\n" );
document.write( "If it starts at the surface, descends 1000 feet, then ascends 1000 feet, it's back at the surface.<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Descent of +1000 ft = -1000 feet<BR>\n" );
document.write( "Ascent = +1000 feet<BR>\n" );
document.write( "The sum is zero.<BR>\n" );
document.write( "==========================<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );