Monday, October 24, 2011

P5 Average, (P6 Algebra?)




Let the original number of books be 1u.

$8 x 1u   +   $32   =    $12  x   ( 1u + 1 )
   $8u      +   $32   =    $12u  +   $12
          $32 - $12    =    $12u  -  $8u
              $20         =     $4u
                 1u        =      $20 / $4  =  5

Number of books now = 5+1 = 6