1.bacteria quadruples everyhour. If a container with these bacteria was half full at 10:00 am. at what time was it one eighth full?
answer:9:00am..
2.if y is not equal to 3, and 3x/y is a prime integer greater than 2, which of the following must be true?
I.x=Y
II Y=1
IIIx and y are prime integers
A none
b I only
c II only
D III only
E i and III
answer: A, my question is why I is not correct, when X=y, 3x/y= 3 is is a primer integer than 2...
3.a coin that is tossed will land heads or tails, and each outcome has equal probability. what is the probability that the coin will land heads at least once on two tosses?
answer:1/4, why not 3/4 since 1-1/2*1/2=3/4,
thank you thank you thank you!作者: newolder 时间: 2011-3-23 19:33
