一道GMAT In a certain game,a large container is filled with re

一道GMAT
In a certain game,a large container is filled with red,yellow,green,and blue beads worth,respectively,7,5,3,and 2 points each .A number of beads are then removed from the container.If the product of the point values of the removed beads is 147,000,how many red beads were removed?
(A)5
(B)4
(C)3
(D)2
(E)0
我知道是D 求翻译，

在一个游戏里面：一个容器里装着红,黄,绿,蓝色珠子,分别对应7,5,3,2分.从容器中移除珠子得到的分数是147000,求移走的红色珠子的次数.
翻译成数学语言：
147000=7的a次方×5的b次方×3的c次方×2的d次方.求a是多少.
其实就是把147000分解成很多因子,看看跟7的关系,用147000除7看能除多少次,（147000=7的“平方”+3000）很显然是2次.