[转帖]11月10号的一些数学JJ

smart

考完后放松了一阵，天天替女儿洗尿布中。。。JJ忘了不少。

数据充分题
There are 5 books on a shelf, some are english, the others are spanish. Randomly pick two, what is the probability that at least 1 is english?
1. probability of the two books are both spanish is 1/10
2. probability of the two books are both english is 3/10

If m and k are consective even numbers, is k > m?
1. m+2 and k-2 are not consecutive even number
2. k-1 and m+3 are consecutive odd number
(我记不清真确题目是啥样的了，意思是这样）

if product a cost $8 and sells at $10, and product b cost $9.5 and sells at $13,  then for a total of 834 products sold, is  the net profit exceeding 2000?
1. more than 1/2 of the product sold is product a
2. at least 100 product b is sold.

k is a positive integer. if 2^k is devided by 10, what is the remainder?
1. k is the multiple of 10
2. k is the multiple of 4

l and t are two lines on the x-y plane. Is the slope of l greater than the slope of t?
1. l intersect x axis at (1,0) and t intersect x axis at (-1,0)
2. l intersect t on the positive segment of the y axis.

if 5^(-x) > 3 ^(-y), is x >y ?
1. xy>0
2. (不记得了，这题毁了我一半脑细胞，还没做出来）

brand A syrup is stored in a cylinder shaped barrel  of height h and diameter D. brand B syrup is stored in a barrel of height 2h and diameter T. Which one is cheapter per liter?
1. 3D=5T
2. A sells at 13.5$, and B selss at 17$ per cylinder.

其他一些数学题：
if a stock is originally priced at x, then the price increase by s percent, and then the price is again increaced by y dollars, what is the actual percentage by which the stock price increased from x?
（这题其实很搞，一不小心就把表达式写错）