myice

23.(19Q37)

AB

     +BA

AAC

In the correctly worked addition problem shown, where

the sum of the two-digit positive integers AB and BA is

the three-digit integer AAC, and A, B, and C are different digits, what is the units digit of the integer AAC?

A.    9

B.     6

C.     3

D.    2

E.     0

分析一下。11(A+B)=110A+C，C必然为11的倍数，所以为0

(E)

myice

22.(9Q23)

When tossed, a certain coin has equal probability of landing on either side.  If the coin is tossed 3 times, what is the probability that it will land on the same side each time?



A.    1/6

B.     2/9

C.     6/11

D.    9/16

E.     3/4

独立事件。第一次概率为，第二次1/2,第三次1/2，一共是1×1/2×1/2=1/4

(B)