325. A knife company enlisted N people to sale 200 knives each, and each man then enlisted N more people to sell 200 knives each. If everyone sold their 200 knives, what is the value of N?
1). The first N people sold 1/9 of all knives sold.
326. Someone is trying to remember a phone number but cannot remember the whole number. He remembers 286-XXXX. He also remembers that the last 4 numbers must contain two 2 and a 7 and a 9. How many possible combinations are there?
329. Someone has $62.00 to spend. Her shopping list includes a $16.95 purse, a $21.00 shirt, and a $39.50 telephone. She must pay 6 percent sales tax on her purchases. Which items should she buy if she wants to spend as much of the $62.00 as possible?
330. If the sum of all positive factors of integer N is 2N, the integer is a perfect number. Or, a perfect number is a whole number, an integer greater than zero; and when you add up all of the factors less than that number, you get that number. For example, the factors of 6 are 1, 2, 3 and 6. 1 + 2 + 3+6 = 12. 28 also is a perfect number.
What is the sum of all reciprocals of positive factors of 28?
答案2。
The factors of 28 are 1, 2, 4, 7, 14and28, so,1+1/2+1/4+1/7+1/14+1/28=2
355.Mary invested M dollars for interest rate n percent simple annually and Kevin invested K dollars for x percent compound semiannually whose total interest is more in first two（我的题是一年） years 1) M >K 2) n>x
379. When x+y is divided by 5, the remainder is 1; when x+z is divided by 5, the remainder is 2; when y+z is divided by 5, the remainder is 3. What is the remainder when x+y+z is divided by 5?
余3。
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380. 函数@K=Ｋ＋１若Ｋ为奇／＝Ｋ－１若Ｋ为偶，求＠Ａ平方＋＠Ｂ为奇还是偶 1）a is even 2) b is odd
393.61.scientist studies the migration trend of a group of geese. The group contains 30% male geese. Among the geese that later on migrated, 20% are male. What is the ratio of migration factor for male geese to the migration facotr for female geese? (migration factor for sex X = number of migrated individual with sex X/total number of individuals with sex X)
Answer:
Let x be the number of geese, and y be the number of migrating geese.
Then, the male goose migrating rate is 20%y/30%x=2y/3x
The female goose migrating rate is 80%y/70%x=8y/7x
The ratio between two rates is (2y/3x)/(8y/7x)=7/12
393.61.scientist studies the migration trend of a group of geese. The group contains 30% male geese. Among the geese that later on migrated, 20% are male. What is the ratio of migration factor for male geese to the migration facotr for female geese? (migration factor for sex X = number of migrated individual with sex X/total number of individuals with sex X)
Answer:
Let x be the number of geese, and y be the number of migrating geese.
Then, the male goose migrating rate is 20%y/30%x=2y/3x
The female goose migrating rate is 80%y/70%x=8y/7x
The ratio between two rates is (2y/3x)/(8y/7x)=7/12
401.2A museum 卖票从早上9:00到17:55 (INCLUSIVE) 的时间里，每5分钟卖出 a group of 30 张票，regular price is $10 , student price is $6，regular tickets的数量是as three times as student tickets问revenue?
405. A jar contains 10 red balls and 10 green balls. If 3 balls are removed at random without replacement, what is the probability that all 3 balls removed from the jar are green?
406. A bathroom door with a timer that sets the light reset for 15 minutes everytime someone enter or exit, ie if the door is opened by someone, the timer will turn the light on for fifteen minutes unless the door is opened again to reset it for another fifteen minutes estimated minutes that the light is off during to . A chart is given with the time that the door is opened during the period 8:00 8:03 .........9:39 (can only remember these end time, just be familiar with the meaning, I spent a lot of time on understanding the problem)
407. how many canyons in the box? 1) envenly divided by a group of four kids, 3 leftover 2) .........................by a group of three kids, 2 leftover (not sure about the number)
408. Mary invested M dollars for interest rate n percent simple annually and Kevin invested K dollars for x percent compound semiannually whose total interest is more in first two years 1) M >K 2) n>x
409. Pumps A, B, and C were used to fill a tank. If rate of A ，is greater than rate of B，is greater than the rate of C reported here? (1) A and B together take half the time as C (2) B takes 3/4th of time taken by C
411. If the smallest number in a set of positive integers is 3, how many numbers does the set have? (1) The set is average of 6 (2) Range of the set is equal to the average of the set
413. If a prime factor multiplied by the number of all the different product than the square root of it. it is a certain number (for a definition I have forgotten), and then asked, what is below the minimum possible number. reference Ans: 96
414. In warehouse there are some boxes divided in stacks, each has 12.After adding 60 more, each has 14.How many boxes before adding? 1)boxes<110 before adding 2)boxes<120 after adding
417. A is ahead of B by 10m, at different constant speed in the same direction. Something about who is over he speed limit. (1) B组 speed is 10m/h faster than the speed limit and A组 is 10m/h slower than the speed limit (2) B组 speed is ?/P>
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发表于 2006-10-20 01:06:00
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