<p>Plumbing Company will send of team of 3 plumbers to work on a job. They have 4 experts and 4 trainees. The team of 3 will consist of 1 expert and 2 trainees. How many different teams are possible. </p>
<p>I did it like this: 4(experts) X 4(trainees) X 3(trainees because there are only 3 left now for the 2nd spot). This comes out to be 48 but the answer is 24. Why doesn't my method work, and when would it work?</p>
<p>I've seen this problem.
You did everything right on except for the trainee part. There it is a combination, not a permutation. have you heard of those? Here, the order does not matter, so you must divide 4x3 by 2, because there's 2 ways to pick each pair of plumbers. (i.e. picking plumber A then plumber B is the same as picking plumber B first, then plumber A). your method would only work when order does matter. (i.e. maybe ways to arrange flowers?)</p>
<p>note : you would not always divide by 2. If you were picking 3 trainee plumbers you would divide by 3</p>
<p>Luckily, answering this question doesn't make you lose one quarter of a point, but how much does one question take off usually on the SAT for each section? The Blue book scale won't give the perfect answer; have you taken the SAT before? Or if anyone else has, how many questions did you get wrong to get your score?</p>
<p>For the umpteenth time:</p>
<p>Consolidated</a> List of Blue Book Math Solutions, 3rd ed. is a great resource that is a shame not to use.</p>
<p>Look there for 657 / 15.</p>