document.write( "Question 830889: The average score of 4 students in a test was 60 marks. If the difference in scores between the top 3 students is 5 marks each, and the last student is 15 marks behind the 3rd student, how many marks did the last student receive? \n" ); document.write( "
Algebra.Com's Answer #500995 by JulietG(1812)\"\" \"About 
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Let A be the top mark, B be the second, C be the third, and D be the bottom.
\n" ); document.write( "Here's what we're told in the problem:
\n" ); document.write( "(A + B + C + D)/4 = 60
\n" ); document.write( "or, A + B + C + D = 240 (I just multiplied each side by 4 to get rid of the fraction)
\n" ); document.write( "D = A - 5 - 5 - 15
\n" ); document.write( "C = A - 5 - 5
\n" ); document.write( "B = A - 5
\n" ); document.write( ".
\n" ); document.write( "Now we can put those values into the original equation.
\n" ); document.write( ".
\n" ); document.write( "A + (A-5) + (A-10) + (A-25) = 240
\n" ); document.write( "Add the As
\n" ); document.write( "4A -5 -10 -25 = 240
\n" ); document.write( "Do the subtraction
\n" ); document.write( "4A - 40 = 240
\n" ); document.write( "Add 40 to each side
\n" ); document.write( "4A = 280
\n" ); document.write( "Divide each side by 4
\n" ); document.write( "A = 70
\n" ); document.write( ".
\n" ); document.write( "Let's plug it back in to the original question to prove it.
\n" ); document.write( "(A)70 + (B)65 + (C)60 + (D)45 does indeed equal 240.
\n" ); document.write( "Success!
\n" ); document.write( ".
\n" ); document.write( "That must have been a very difficult exam!
\n" ); document.write( " \n" ); document.write( "
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