document.write( "Question 251983: If Beth gets a 97 on her next math test, her average will be 90. If she gets 73, her average will be 87. How many tests has Beth already taken? \n" ); document.write( "
Algebra.Com's Answer #183724 by palanisamy(496)\"\" \"About 
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First method\r
\n" ); document.write( "\n" ); document.write( "Let the total number of tests taken by Beth be x.
\n" ); document.write( "If Beth gets a 97 on her next math test, her average will be 90
\n" ); document.write( "If she gets 73, her average will be 87.
\n" ); document.write( "As of now, 90x - 97 = 87x-73
\n" ); document.write( " 90x-87x = 97-73
\n" ); document.write( " 3x = 24
\n" ); document.write( " x = 8
\n" ); document.write( "So, the number of tests already undertaken = 8-1 = 7\r
\n" ); document.write( "\n" ); document.write( "Second Method
\n" ); document.write( "Let the number of tests already undertaken be x and
\n" ); document.write( " the total marks secured be n.
\n" ); document.write( "If Beth gets a 97 on her next math test, her average will be 90
\n" ); document.write( " (n+97)/(x+1) = 90
\n" ); document.write( " n+97 = 90(x+1)
\n" ); document.write( " n+97 = 90x+90
\n" ); document.write( " n+7 = 90x ......(1)
\n" ); document.write( "Next,
\n" ); document.write( " If she gets 73 in the next test, her average will be 87
\n" ); document.write( " (n+73)/(x+1) = 87
\n" ); document.write( " n+73 = 87(x+1)
\n" ); document.write( " n+73 = 87x+87
\n" ); document.write( " n = 87x + 14 ......(2)
\n" ); document.write( " (1)-(2):
\n" ); document.write( " 7 = 3x-14
\n" ); document.write( " 21 = 3x
\n" ); document.write( " 7 = x
\n" ); document.write( "So, the number of tests already undertaken = 7\r
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