mmelissa0908的部落格

Percentage

概念： https://www.mathsisfun.com/percentage.html

練習題目：

http://mathforum.org/library/drmath/sets/select/dm_percent_increase.html

http://222.208.6.176:8084/YFB12/examTab_getExam.action?su_Id=2&ex_Id=7605

Keyword：

      (1.) 30000 is greater than 4000 by what percent?                              

                       30000      是大於        4000 多少百分比

                   ⇨26000　　是4000 的多少百分

　　　　　⇨26000/4000= 6.5 = 650%

   （2）the original price of X was increased by 25%, A sale brought the price of X back down to it't original price.  The sale reduce the new price of X by what percent?

          詳解2.  多少百分比的計算方式為  （兩個數字的差）／先前的數字

                 the original price of X was increased by 25%, 假設X原來為100

                  ⇨現在百分比＝原來的 1 ＋ 增加的0.25＝1.25X＝125

                     125-100／125＝20%

Arithmetic

http://quedb.com/data/gre/quant/arithematic/np.htm (題目＋英文解說）