文章：According to many analysts, labor-management relations in the United States are undergoing a fundamental change: traditional adversarialism is giving way to a new cooperative relationship between the two sides and even to concessions from labor. These analysts say the twin shocks of nonunion competition in this country and low-cost, high-quality imports from abroad are forcing unions to look more favorably at a variety of management demands: the need for wage restraint and reduced benefits as well as the abolition of "rigid" work rules, seniority rights, and job classifications. Sophisticated proponents of these new developments cast their observations in a prolabor light. n return for their concessions, they point out, some unions have bargained for profit sharing, retraining rights, and job--security guarantees. Unions can also trade concessions for more say on the shop floor, where techniques such as quality circles and quality-of-work­ life programs promise workers greater control over their own jobs. Unions may even win a voice in investment and pricing strategy, plant location, and other major corporate policy decisions previously reserved to management. Opponents of these concessions from labor argue that such concessions do not save jobs, but either prolong the agony of dying plants or finance the plant relocations that employers had intended anyway. Companies make investment decisions to fit their strategic plans and their profit objectives, opponents point out, and labor costs are usually just a small factor in the equation. Moreover, unrestrained by either loyalty to their work force or political or legislative constraints on their mobility, the companies eventually cut and run, concessions or no concessions. Wage-related concessions have come under particular attack, since opponents believe that high union wages underlay much of the success of United States industry in this century. They point out that a long-standing principle, shared by both management and labor, has been that workers should earn wages that give them the income they need to buy what they make. Moreover, high wages have given workers the buying power to propel the economy forward. f proposals for pay cuts, two-tier wage systems, and subminimum wages for young workers continue to gain credence, opponents believe the U.S. social structure will move toward that of a less-developed nation: a small group of wealthy investors, a sizable but still minority bloc of elite professionals and highly skilled employees, and a huge mass of marginal workers and unskilled laborers. Further, they argue that if unions willingly engage in concession bargaining on the false grounds that labor costs are the source of a company's problems, unions will find themselves competing with Third World pay levels-a competition they cannot win. 想请问郭老师，这题opponents观点是在第三段，但是原文和选项要怎么对照呢...怎么从观点看出态度？

GMAT数学（博智教材）第62页：If X is equal to the sum of the even integers from 40 to 60, inclusive, and y is the number of even integers from 40 to 60, inclusive, what is the value of x+y? X=40+42+44......60=550 Y=(60-40)/2+1=11, 答案应该是561，为什么书后面的答案显示是560？

数学书61页36题，一个男的卖每条7块的领带和每件14元的衬衫。如果他总共卖了10件，110元，求卖了几条领带？ 我得小数，选项里没有。

DS：5个数中 median 小于 average ；另外7个数也median 小于 average，然后这12个数没有重复的，12个数放在一个数集里面，问是不是median 小于average？ 条件1：7个的average 小于 5个的average 条件2：7个的median 小于 5个的 median

DS：一个三位数xyz是9的倍数，问x+y+z=9？ 条件1：x+y+z<15 条件2：x+y+z>8

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这种ds题目里面有比例关系的我特别弱，老师能帮我梳理一下这种题拿到药怎么入手吗

老师这个题目帮我讲解一下，机经答案我看了还是不明白。

这个题目机经写的特别复杂，老师能帮我讲一下吗

老师，能帮我梳理一下这个题目吗

题目：of the 200 students at college T majoring in one or more of the sciences, 130 are majoring in chemistry and 150 majoring in biology. If at least 30 of the students are not majoring in either chemistry or biology, then the number students majoring in both biology and chemistry could be any number from a) 20 to 50 b) 40 to 70 c) 50 to 130 d) 110 to 130 e) 110 to 150 问题：这道题能理解到是用集合的知识点，但是无论怎么做都无法突破，得到最后结果。还请老师讲解。谢谢