为何下面这个题选C呢， 我怎么看怎么觉得选E。。。 求指点
During July, a mail order retailer received 3300 order for amounts less than $100, and 1100 orders for amounts of at least $100. what was the average size of an order in July?
(1) The gross sales from the orders less than $100 equaled the gross sales from the orders greater than $100
(2) The orders for less than $100 account for a total of $134000 in gross sales作者: haileywang 时间: 2011-2-12 07:34
$X : total $ for orders <$100
$Y: total $ for orders =$100
$Z: total $ for orders >$100
Stimulus give the # of orders for $X and the # of orders for ($Y + $Z)
1) X = Z
2) X= 134,000
So combining 1) and 2), you get X=Z= 134,000. But we still do not know Y.
LZ is right. Choose E.作者: avalon9527 时间: 2011-2-12 08:11
average size of an order = total gross sales / 4400 orders
1) the gross sales of amount <100 = the gross sales of amount >=100
2) the gross sales of amount <100 = 134000
so, if both 1) and 2) are true, then the average size should be 134000*2/4400作者: avalon9527 时间: 2011-2-12 08:17
it seems i made a mistake.作者: bigpig 时间: 2011-2-12 14:37
