Question

sat数学题

The AP company will send a team of 3plumbers to work on a certain job.The company has 4 experienced plumbers and 4 trainees .If a team consists of 1 experieced plumber and trainees.how many different such teams are possible?
我是4乘4乘3但是答案是24

The sum of two numbers that differ by1is t.In terms of t,what is the value of the greater of the two numbers?
少打了一个，是If a team consists of 1 experieced plumber and 2 trainees.

为什么都说4*3/2=6中情况
我想的是第一个人有4种情况，第二个有3种情况

Answer 1

解：依题意，根据组伍枝销合定理，从4个 熟练的管子工中任搭型选3个出来有4种情况，从4个新手中任选2个出来出来有4*3/腔游2=6种情况，满足题设条件的情况共有4*6=24种。

Answer 2

因为“If a team consists of 1 experieced plumber and trainees”中trainees 是复数，所以应该是2个trainees，所以是4*（4*3/2）=24
第一个人4个中挑一个，4种，剩下两个人，是从4个中无次序的挑两个，从高中数学的排列组合得出，是4*3/2，简单的说，就是a.b.c.d中渣空春，1.a选 另一人有 bcd 三种,2.b已选 有两种 和cd 选a和之前的重复，3。c 一种 和d
则一共有6种；也就是说，先从四个中挑一个如耐，再在剩下三个中挑一个，并且是无排序的亏稿，所以要除以2排除重复的情况，比如ab和ba。