document.write( "Question 1117373: The arithmetic mean of six grades is 87. If the lowest grade is dropped, the mean is 89. What is the lowest grade?
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #732437 by greenestamps(13203) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "Subtract the unknown test score (x) from the total of all 6 scores (87*6); that gives you the total of the other 5 scores (89*5):

\n" ); document.write( " $\"87%2A6-x+=+89%2A5\"$
\n" ); document.write( " $\"522-x+=+445\"$
\n" ); document.write( " $\"x+=+77\"$

\n" ); document.write( "The lowest score was 77.

\n" ); document.write( "Or here is another way to solve this kind of problem. If you understand it, it will get you to the answer faster than the formal algebraic method shown above.

\n" ); document.write( "When one score is dropped, the average of the other 5 scores increases from 87 to 89, an increase of 2.
\n" ); document.write( "The average increase of 2 on 5 test scores means there are 10 \"additional\" points total.
\n" ); document.write( "To keep things balanced, the score that was dropped had to have 10 \"too few\" points.
\n" ); document.write( "So the test score that was dropped was 10 points below the average, or 87-10 = 77. \n" ); document.write( "

\n" );