问题如下图：
选项：
A. 
B. 
C. 
解释：
斜率与弹性的关系如何理解，是互为倒数吗？
NO.PZ2016010802000024问题如下The market manfunction for four-yeprivate universities is given the equationQr =84−3.1Ppr+0.8I+0.9PpuwhereQr is the number of applicants to private universities per yein thousan, Ppris the average priof private universities (in thousan of US, I is the householmonthly income (in thousan of US, anPpu is the average priof public (government-supporte universities (in thousan of US. Assume thPpr is equto 38, I is equto 100, anPpu is equto 18.The prielasticity of manfor private universities is closest to:A.–3.1.B.–1.9.C.0.6.is correct.From the manfunction:ΔQr/ΔPpr=−3.1Solve for Qr = 8r−3.1Ppr+0.8I+0.9Ppu=84−3.1(38)+0.8(100)+0.9(18)=62.4Ppr = 38, prielasticity of man(ΔQr/ΔPpr)(Ppr/Qr)=(-3.1)(38/62.4)=-1.9考点需求价格弹性解析题目给出了需求函数的表达式，带入数字，先求的私立大学的需求量，即Qr = 8r−3.1Ppr+0.8I+0.9Ppu=84−3.1(38)+0.8(100)+0.9(18)=62.4之后我们再利用需求价格弹性公示求解，即，(ΔQr/ΔPpr)(Ppr/Qr)=(-3.1)(38/62.4)=-1.9为什么这题用的是-3.1。而不是0.9
–1.9. 0.6. B is correct. From the manfunction: ΔQr/ΔPpr=−3.1 Solve for Qr = 8r−3.1Ppr+0.8I+0.9Ppu =84−3.1(38)+0.8(100)+0.9(18)=62.4 Ppr = 38, prielasticity of man(ΔQr/ΔPpr)(Ppr/Qr)=(-3.1)(38/62.4)=-1.9 考点需求价格弹性 解析题目给出了需求函数的表达式，带入数字，先求的私立大学的需求量，即 Qr = 8r−3.1Ppr+0.8I+0.9Ppu =84−3.1(38)+0.8(100)+0.9(18)=62.4 之后我们再利用需求价格弹性公示求解，即， (ΔQr/ΔPpr)(Ppr/Qr)=(-3.1)(38/62.4)=-1.9-3.1是怎么算出来的
题目不是问pu的价格弹性 怎么答案用pr的-3.1
对不起，请问老师这一题能不能再详细解释一下？谢谢！问一道题：NO.PZ2016010802000024 [ CFA I ]
