标题: OG 139 不解，要是考试真碰到这种题肿么办。。。 [打印本页] 作者: angeldancer 时间: 2011-6-3 04:39 标题: OG 139 不解，要是考试真碰到这种题肿么办。。。 A restaurant meal cost $35.50 and there was no tax. If the tip was more than 10 percent but less than 15 percent of the cost of the meal, then the total amount paid must have been between A. $40 and $42 B. $39 and $41 C. $38 and $40 D. $37 and $39 E. $36 and $37
为什么不是A啊？。。。。 RT，算出来最小值是39.05，最大值是40.825（约等于40.83）钱可以精确到小数点最后两位，买东西不可以不给零，既然最小值是39.05，为什么5个cents 可以舍要选B啊？作者: lnl555 时间: 2011-6-3 07:40
........TOTAL AMOUNT的范围是【39.05 ，40.825】 A 显然错了啊。。40比39.05大好吧。。。 B是对的 包含[39.05,40.825]的区间作者: sdcar2010 时间: 2011-6-3 08:31
This is must be true.
What about $41.10? It is in A but not in B. However, $41.10 can never be the total payment.