※ 引述《piwei (what happen)》之铭言： : 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 s 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$200 : more than the cost of a square slab that is 2 meters long and 0.1 meter thick. : 答案是D : 我觉的是E(天差地远的) : 麻烦帮忙解答一下 头都快想破掉了 我的想法跟楼上不太一样 cost 与 thickness 成正比且与 length 平方成正比 所以 1) 假设 2 meter long, 0.2 meter thick 的 slab 为 X 所以 2 meter long, 0.1 meter thick 的 slab 则为 X/2 X-X/2 = 160 可得X为320 2 meter long, 0.1 meter thick 为160 (320/2) 题目问 3 meter long, 0.1 meter thick 则为 160 * (3/2)的平方 所以答案为360 2) 相同假设 3 meter long, 0.1 meter thick 的 slab 为 X 所以 2 meter long, 0.1 meter thick 的 slab 则为 X * 4/9 X - 4/9*X = (5/9)X = 200 可得X = 360 以上是我的想法 有错请指正 ^^ --

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