由于产品1的价格上涨10%，销售量下降20%，新销售额 = (1.1)($50)(200,000个)(0.8) = $8,800,000. 由于产品2与产品1互补，它的销售量也会有20%的下降，这样产品2的新销售额 = (0.8)($1,500,000) = $1,200,000。产品3的销售量有5%的增长，这样产品3的新销售额 = (1.05)($9,000,000) = $9,450,000。产品1, 2和3的总的销售额是 = $8,800,000 + $1,200,000 + $9,450,000 = $19,450,000。$19,450,000比20,500,000少$1,050,000。
