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Factors, Multiples, and Remainders Videos 4 videos

SAT Math 3.4 Numbers and Operations
198 Views

SAT Math 3.4 Numbers and Operations

SAT Math 4.5 Numbers and Operations
203 Views

SAT Math 4.5 Numbers and Operations

SAT Math 5.5 Numbers and Operations
182 Views

SAT Math 5.5 Numbers and Operations

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SAT Math 5.5 Numbers and Operations 182 Views


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Description:

SAT Math 5.5 Numbers and Operations

Language:
English Language

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…

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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