The function f is defined for each positive three digit integer n by f(n)=2^x3^y5^z ( 2 的x次方乘以 3 的y 次方乘以5的z次方，where x,y and z are the hundreds, tens, and unit digit of n, respectively. If m and v are three-digit positive integer such that f(m)=9f(v), then m-v=?

key 20

完全没有思路。。。

gwd 21 7题

In the rectangular coordinate system, point (4,0) and (-4,0 ) both lie on circle c, what is the maximum possible value of the radius of c.

长方形和 circle 有什么关系么？

gwd 21 17题

There are 5 cars to be displayed in 5 parking spaces with all the cars facing the same direction. Of the 5 cars, 3 cars red, 1 is blue, and 1 is yellow. If the cars are identical except for color （意思是相同颜色的车不能放一块?), how many different display arrangements of the 5 cars all possible?

key :20

gwd 11 3题

The sides of a square region, measured to the nearest centimeters, are 6 centimeters long. The least possible value of the actual area of the square region is ?

6cm难道不是就在说边长么？

。。。。。

ding !!!!!!!!!!