几道数学题求解

woaihenglia

不好意思又要麻烦各位了。有点读不懂题，阅读不过关....又要麻烦各位了

1: is the positive integer j  divisible by a greater number of different prime numbers than the positive integer k?

2:two members of a club are to be selected to represent the club at a national meeting. If there are 190 different possible selections of the 2 members, how many member does club have

3:A certain meter records voltage between 0 volts and 10 volts, inclusive. If the average( arithmetic mean) value of 3 recordings on the meter was 8 volts, what was the smallest possible recording, in volts?

sdcar2010

2:two members of a club are to be selected to represent the club at a national meeting. If there are 190 different possible selections of the 2 members, how many member does club have

190 = (19 * 20) / 2.  The club has 20 members.

sdcar2010

3:A certain meter records voltage between 0 volts and 10 volts, inclusive. If the average( arithmetic mean) value of 3 recordings on the meter was 8 volts, what was the smallest possible recording, in volts?

The total of volts for the 3 recordings = a + b + c = 3*8 = 24
In order to get the smallest possible recording, you need to force the other 2 recordings at the maximum value, which is 10 in our case.  So remove the two 10's from 24, you got 4 volts as the smallest possible recording.

woaihenglia

sdcar兄，俺还是没看明白表达第二题啥意思，还有你的公式俺也没看懂，麻烦讲解细一点啊，跪谢

sdcar2010

If you have n members in a group and you want to select two members for a team, how many possible teams do you have?

For the first member, you have n choices.  For the second member, you have n-1 choices.  The total number of possible choices for first and second members in a team are n*(n-1).  However, since first A second B is the same as first B second A as a team, the final possible choices for a team is half of that.