请教数学GWD1

freddong

竟然有5道不会，请各位帮忙。谢谢

Q2:

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?

 

A.       0

B.        1/9

C.        2/9

D.       1/3

E.        1

Q10:

A set of numbers has the property that for any number t in the set, t + 2 is in the set.  If –1 is in the set, which of the following must also be in the set?

 

I.                    -3

II.                 1

III.               5

 

 

A.    I only

B.    II only

C.    I and II only

D.    II and III only

E.    I, II, and III

Q17:

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?

 

A.     16%

B.      25%

C.      32%

D.     40%

E.      52%

Q26:

Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y.  At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?

 

A.     4

B.      6

C.      8

D.     10

E.      12

Q31:

A positive integer n is said to be “prime-saturated” if the product of all the different positive prime factors of n is less than the square root of n.  What is the greatest two-digit prime-saturated integer?

 

A.     99

B.      98

C.      97

D.     96

E.      95

paleo_gracia

Hi I may have the answers for 10, 17, 26.

10) -1+2=1,1+2=3, 3+2=5...

17) 16/64=.25 u might want to read the question carefully

26) use the fomula 1/y+1/(2+y)=5w/12

btw, anyone knows at most how many incorrect answers could lead to math 50+? thanks~

freddong

应该错一个，50＋

kaisandy

how about Q31 answer?

sunrains

2）3/(3*3)=1/3
31题按我的理解没有正确选项。。。。。。。

a10285

“prime-saturated”定义为n所有互异的质因数的乘积小于根号n
ze一一验证abcde
A.      99 互异质因子为3和11，则3*11>根号99

B.      98互异质因子为2和7，则2*7>根号98

C.      97本身为质数显然>genhao97

D.     96互异质因子为2和3，则2*3<根号96

E.      95互异质因子为5和19，则5*19>genhao95

选D

sunrains

同意5楼，刚把4当质数了。。。脑子被门挤了。。。

davidcub

2) 应该是p3/27吧 不应该是2/9么？

迷途小孩

同问26 我算不出答案来···