标题: 请教几道GWD数学题 求思路、过程 [打印本页] 作者: cxks01 时间: 2011-10-24 20:05 标题: 请教几道GWD数学题 求思路、过程 Q13: An integer greater than 1 that is not prime is called composite.If the two-digit integer n is greater than 20, is n composite? (1)The tens digit of n is a factor of the units digit of n. (2)The tens digit of n is 2.
Q15: If w, x, y, and z are integers such that 1 < w < x < y < z and wxyz = 462, then z =?
Q18: On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?
Q23: AMOUNT OF BACTERIA PRESENT
Time
Amount
1:00 P.M.
10.0 grams
4:00 P.M.
x grams
7:00 P.M.
14.4 grams
Data for a certain biology experiment are given in the table above.If the amount of bacteria present increased by the same fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.? Q24: The value of (9´107)(9´108) is closest to which of the following? Q25: A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars? Q31: There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines.If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected? Q32: What is the remainder when the two digit, positive integer x is divided by 3? (1)The sum of the digits of x is 5. (2)The remainder when x is divided by 9 is 5. Q33: In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.What percent of the employed people in Town X are females?
Q15: If w, x, y, and z are integers such that 1 < w < x < y < z and wxyz = 462, then z =?
Q18: On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?
Q23: AMOUNT OF BACTERIA PRESENT
Time
Amount
1:00 P.M.
10.0 grams
4:00 P.M.
x grams
7:00 P.M.
14.4 grams
Data for a certain biology experiment are given in the table above.If the amount of bacteria present increased by the same fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.? Q24: The value of (9´107)(9´108) is closest to which of the following? Q25: A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars? Q31: There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines.If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected? Q32: What is the remainder when the two digit, positive integer x is divided by 3? (1)The sum of the digits of x is 5. (2)The remainder when x is divided by 9 is 5. Q33: In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.What percent of the employed people in Town X are females?作者: 王小睿 时间: 2011-10-24 20:10
Q13，应该是A吧 如果十位是个位的factor，那么这个数肯定就不是prime了作者: 王小睿 时间: 2011-10-24 20:12
Q15 wxyz=2*3*7*11， Z=11作者: 无敌可爱多 时间: 2011-10-24 22:08
Q13: An integer greater than 1 that is not prime is called composite.If the two-digit integer n is greater than 20, is n composite? (1)The tens digit of n is a factor of the units digit of n. (2)The tens digit of n is 2.
Q15: If w, x, y, and z are integers such that 1 < w < x < y < z and wxyz = 462, then z =?
把462进行因子分解，分解到质因数的次方形式，就一目了然了。
Q18: On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?
Data for a certain biology experiment are given in the table above.If the amount of bacteria present increased by the same fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.?
Q24: The value of (9´107)(9´108) is closest to which of the following?
=81*10^15 ，自己看看和哪个最接近吧。 Q25: A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?
Q31: There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines.If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?
用C3,8 (8本里任选三本）做分母 C3,4(只选sports magazine)做分子
然后1-上面的分数，得到答案。 Q32: What is the remainder when the two digit, positive integer x is divided by 3? (1)The sum of the digits of x is 5. (2)The remainder when x is divided by 9 is 5.
Q33: In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.What percent of the employed people in Town X are females?
比例问题，做法同18。
这道题就当做是你思考18题的作业了，所以你自己再做一次吧，如果还是做不出来再跟帖问。作者: cxks01 时间: 2011-10-24 23:54
高手再请教一题，是GWD第二套第30题，有个图，我不会怎么插图上来，题目是In the figure, each side of square ABCD has length 1, the length of line segment CE is 1, and the length of line segment BE is equal to the length of line segment DE.What is the area of the triangular region BCE?分不清是平面还是立体图，立体图的话应该是1/2吧？
还有Q24: The value of (9´107)(9´108) is closest to which of the following?
高手再请教一题，是GWD第二套第30题，有个图，我不会怎么插图上来，题目是In the figure, each side of square ABCD has length 1, the length of line segment CE is 1, and the length of line segment BE is equal to the length of line segment DE.What is the area of the triangular region BCE?分不清是平面还是立体图，立体图的话应该是1/2吧？