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Statistics, Data, and Probability I: Drill Set 3, Problem 4. How many different avatars can be created based on the given options?
Statistics, Data, and Probability II Drill 3 Problem 2. Which two sports together make up for the preferences of more than half of all those w...
SAT Math 5.5 Numbers and Operations 182 Views
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Description:
SAT Math 5.5 Numbers and Operations
Transcript
- 00:02
Here’s your shmoop du jour, brought to you by Handshakes.
- 00:06
The best way to pass along bacteria to someone you’ve just met.
- 00:09
Six people are in a room.
- 00:11
If everyone shakes hands one time with each other, how many handshakes take place?
- 00:18
Okay, so either some important business deal is about to go down…
Full Transcript
- 00:21
…or else the annual Sweaty Palm Convention is in town.
- 00:24
Purell, anyone?
- 00:26
All right – we’re looking for the total number of handshakes.
- 00:29
First, each of the 6 people has to shake hands with the 5 other people.
- 00:34
To count these handshakes, let’s multiply 6 by 5... 30.
- 00:39
Oops. By doing that, we’ve over counted… by a lot.
- 00:43
With this method, we’re basically counting person A shaking hands with person B as one handshake
- 00:49
and person B shaking hands with person A as a totally separate handshake.
- 00:54
In reality, when 2 people shake hands with each other, that only counts as 1 handshake.
- 01:00
To be more specific, our number is actually double the real number of handshakes actually happening,
- 01:06
so divide that 30 by 2 and get 15.
- 01:09
That’s a lot of handshaking.
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