标题: 求助~一道prep上的data sufficient [打印本页] 作者: yxlam 时间: 2010-5-11 21:09 标题: 求助~一道prep上的data sufficient The cost of a square slab is proportional to its thickness and also proportional to the square of its length. What is the cost of a square slab that is 3 meters long and 0.1 meter thick? 1.The cost of a square slab that is 2 meters long and 0.2 meter thick is $160 more than the cost of a square slab that is 2 meters long and 0.1 meter thick. 2.The cost of a square slab that is 3 meters long and 0.1 meter thick is $160 more than the cost of a square slab that is 2 meters long and 0.1 meter thick. 答案是D 我选的是C 望NN鼎力相助~ p.s.真杯具..贴个图找了好多地方 最后还是手打好了 T T