柏小颖 · 2020年03月17日
问题如下：
Peter bought a security for $55 in year 1, $60 in year 2, $64 in year 3, $70 in year 4. The harmonic mean of the price will be:
选项：
A. 61.77.
B. 25.
C. 37.04
解释：
A is correct. The harmonic mean : 4/[(1/55) + (1/60) + (1/64) + (1/70)] = 61.77
调和平均数的公式可以列出来，可是怎么计算啊，有好的计算方法吗？我硬算了几遍都是错的NO.PZ2018062016000048 问题如下 Peter bought a security for $55 in ye1, $60 in ye2, $64 in ye3, $70 in ye4. The harmonic meof the priwill be: A.61.77. B.25. C.37.04 A is correct. The harmonic me: 4/[(1/55) + (1/60) + (1/64) + (1/70)] = 61.77 请问这道题如果知道价格，求价格的geometic mean怎么求呀？
NO.PZ2018062016000048问题如下Peter bought a security for $55 in ye1, $60 in ye2, $64 in ye3, $70 in ye4. The harmonic meof the priwill be:A.61.77.B.25.C.37.04A is correct. The harmonic me: 4/[(1/55) + (1/60) + (1/64) + (1/70)] = 61.77这个题，我用考试计算器算出来的是61.83，请问是为什么？小数点设的是6位，误差会有这么大吗……
NO.PZ2018062016000048 问题如下 Peter bought a security for $55 in ye1, $60 in ye2, $64 in ye3, $70 in ye4. The harmonic meof the priwill be: A.61.77. B.25. C.37.04 A is correct. The harmonic me: 4/[(1/55) + (1/60) + (1/64) + (1/70)] = 61.77 RT
