[求助] GWD 27-34 GWD 26-14

diamondivy

GWD 26-14 :

A three-digit code for certain logs uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 according to the following constraints.  The first digit cannot be 0 or 1, the second digit must be 0 or 1, and the second and third digits cannot both be 0 in the same code.  How many different codes are possible?

这题我的答案是
     144  (8*2*9=144)  不过GWD答案是152 ， 不知小妹哪里有想错呢

   望请各位多指点! 感谢!
      

GWD 27-34:

If n is a positive integer, what is the remainder when 3⁸ⁿ⁺³ + 2 is divided by 5?

A.      0

B.      1

C.      2

D.     3

E.      4

 我的算法  3⁸ⁿ⁺³ + 2 = 81²ⁿ * 27+2   所以算出来的数尾数会是 1*7+2=9

这题我的答案是
     E   但GWD答案是
     A (但是我怎么算都没有整除)

也是要麻烦各位帮忙一下了! 感谢感谢。

[此贴子已经被作者于2006-8-24 19:33:16编辑过]

yaoyao99

Please search before you post your questions!  Thank you, =)

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=184062&page=1

涛涛 27-34 —— GIGI版 1-13

http://forum.chasedream.com/dispbbs.asp?BoardID=22&ID=65213

26-14

When 2nd digit = 0 => 3rd digit can be 1 to 9 => 8 * 9 = 72

When 2nd digit = 1 => 3rd digit can be 0 to 9 => 8 * 10 = 80

72 + 80 = 152

diamondivy

Thanks!