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SAT Math Videos 171 videos
SAT Math 1.1 Algebra and Functions. Find an algebraic equation to correspond with the data.
SAT Math 1.1 Geometry and Measurement. What is the circumference of the circle?
SAT Math 1.1 Numbers and Operations. How many combinations of beverage and cereal can be made?
SAT Math 2.3 Statistics and Probability 229 Views
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SAT Math 2.3 Statistics and Probability
SAT Math 2.3 Statistics and Probability
Transcript
- 00:02
Here’s your shmoop du jour, brought to you by Permutations.
- 00:06
The preferred hairstyle of mathematicians.
- 00:09
Six students are arranged in a row.
- 00:12
How many different ways can this happen? And here are the potential answers…
- 00:18
When we are arranging students in a row, we are counting permutations.
Full Transcript
- 00:26
The easy way to solve one of these permutation problems is
- 00:28
to simply take the factorial of the number we are ordering.
- 00:35
In this case…it's 6.
- 00:37
We start with 6 spaces to place the students.
- 00:41
When we go to place the first student, we have 6 to choose from.
- 00:45
Then, for our next slot, there are only 5 left.
- 00:47
With each successive space, there is one less
- 00:50
choice, since another was used up in the previous slot.
- 00:54
Now, to find the possible permutations of students, we simply multiply the number of
- 00:58
choices for all slots together.
- 01:01
Which equals 720, that's 6 factorial.
- 01:04
So we get 720 possible outcomes. Our answer is just (C).
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