The time value of money - German Nande

372,179 views ใƒป 2014-07-03

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: Tal Dekkers
00:09
They say, 'Time is money,'
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ื”ื ืื•ืžืจื™ื, "ื–ืžืŸ ื–ื” ื›ืกืฃ,"
00:11
but what does one really have to do with the other?
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ืื‘ืœ ืžื” ื‘ืืžืช ื”ืงืฉืจ ื‘ื™ืŸ ื”ืฉื ื™ื™ื?
00:14
Meet Sheila!
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ืคื’ืฉื• ืืช ืฉื™ืœื”!
00:15
She just got her first big bonus.
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ื”ื™ื ืงื™ื‘ืœื” ืขื›ืฉื™ื• ืืช ื”ื‘ื•ื ื•ืก ื”ืจืืฉื•ืŸ ืฉืœื”.
00:19
Sheila knows exactly what she wants to do with that money.
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ืฉื™ืœื” ื™ื•ื“ืขืช ื‘ื“ื™ื•ืง ืžื” ื”ื™ื ืจื•ืฆื” ืœืขืฉื•ืช ืขื ื”ื›ืกืฃ.
00:22
She's had her eye on a nice convertible for a while now.
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ื”ื™ื ืฉืžื” ืขื™ืŸ ืขืœ ืžื›ื•ื ื™ืช ืคืชื•ื—ื” ื›ื‘ืจ ื›ืžื” ื–ืžืŸ.
00:25
Yes, Sheila, that's a nice car!
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ื›ืŸ, ืฉื™ืœื”, ื–ื• ืžื›ื•ื ื™ืช ื ื—ืžื“ื”!
00:28
Oh, looks like Sheila is a little short.
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ืื•ื”, ื ืจืื” ืฉื—ืกืจ ืœืฉื™ืœื” ืงืฆืช ื›ืกืฃ.
00:31
But wait!
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ืื‘ืœ ื—ื›ื•!
00:32
She has an idea.
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ื™ืฉ ืœื” ืจืขื™ื•ืŸ.
00:34
Sheila is a smart cookie.
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ืฉื™ืœื” ื”ื™ื ื‘ื—ื•ืจื” ื—ื›ืžื”.
00:35
She knows that if she deposits the money for a year
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ื”ื™ื ื™ื•ื“ืขืช ืฉืื ื”ื™ื ืชืคืงื™ื“ ืืช ื”ื›ืกืฃ ืœืฉื ื”
00:38
instead of buying the car today,
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ื‘ืžืงื•ื ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช ื”ื™ื•ื,
00:40
she will earn interest.
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ื”ื™ื ืชืจื•ื•ื™ื— ืจื™ื‘ื™ืช.
00:42
Then she'll be able to afford the car.
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ืื– ื”ื™ื ืชื•ื›ืœ ืœื”ืจืฉื•ืช ืœืขืฆืžื” ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช.
00:45
Sheila knows that the value of her deposit one year from now
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ืฉื™ืœื” ื™ื•ื“ืขืช ืฉื”ืขืจืš ืฉืœ ื”ื”ืคืงื“ื” ืฉืœื” ืฉื ื” ืžืขื›ืฉื™ื•
00:49
will equal the money deposited today plus the interest earned.
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ื™ื”ื™ื” ืฉื•ื•ื” ืœื›ืกืฃ ืฉื”ื•ืคืงื“ ื”ื™ื•ื ื•ืขื•ื“ ื”ืจื™ื‘ื™ืช.
00:53
We call Sheila's money deposited today
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ืื ื—ื ื• ืงื•ืจืื™ื ืœื”ืคืงื“ื” ืฉืœ ืฉื™ืœื” ื”ื™ื•ื
00:56
the present value of money.
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ื”ืขืจืš ื”ืขื›ืฉื•ื•ื™ ืฉืœ ื”ื›ืกืฃ.
00:58
And the value of Sheila's deposit next year
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ื•ื”ืขืจืš ืฉืœ ื”ื›ืกืฃ ืฉืœ ืฉื™ืœื” ื‘ืฉื ื” ื”ื‘ืื”
01:01
is the future value of money.
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ื”ื•ื ื”ืขืจืš ื”ืขืชื™ื“ื™ ืฉืœ ื”ื›ืกืฃ ืฉืœื”.
01:03
What connects one to the other?
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ืžื” ืžื—ื‘ืจ ืื—ื“ ืœืฉื ื™?
01:04
The interest rate,
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ืฉื™ืขื•ืจ ื”ืจื™ื‘ื™ืช,
01:06
also known as the time value of money.
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ืฉื™ื“ื•ืข ื’ื ื›ืขืจืš ื”ื–ืžืŸ ืฉืœ ื”ื›ืกืฃ.
01:10
Now, with a little bit of rearranging,
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ืขื›ืฉื™ื•, ืขื ืžืขื˜ ืืจื’ื•ืŸ ืžื—ื“ืฉ,
01:11
we can figure out the future value of Sheila's money
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ืื ื—ื ื• ื™ื›ื•ืœื™ื ืœื—ืฉื‘ ืืช ื”ืขืจืš ื”ืขืชื™ื“ื™ ืฉืœ ื”ื›ืกืฃ ืฉืœ ืฉื™ืœื”
01:15
with this equation.
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ืขื ื”ืžืฉื•ื•ืื” ื”ื–ื•.
01:16
So in a year, the future value will be $11,000.
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ืื– ื‘ืขื•ื“ ืฉื ื”, ื”ืขืจืš ื”ืขืชื™ื“ื™ ื™ื”ื™ื” $11,000.
01:21
Well, it's been a year!
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ื•ื‘ื›ืŸ, ืขื‘ืจื” ืฉื ื”!
01:22
And there's Sheila, with enough money to buy the car.
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ื•ื”ื ื” ืฉื™ืœื”, ืขื ืžืกืคื™ืง ื›ืกืฃ ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช.
01:25
Sheila really understands the future value of money.
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ืฉื™ืœื” ื‘ืืžืช ืžื‘ื™ื ื” ืืช ื”ืขืจืš ื”ืขืชื™ื“ื™ ืฉืœ ื”ื›ืกืฃ.
01:28
Now, I just hope she understands the speed limit!
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ืขื›ืฉื™ื•, ืื ื™ ืจืง ืžืงื•ื•ื” ืฉื”ื™ื ืžื›ื™ืจื” ืืช ื—ื•ืงื™ ื”ืชื ื•ืขื”!
01:31
Now, meet Timmy.
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ืขื›ืฉื™ื•, ืคื’ืฉื• ืืช ื˜ื™ืžื™.
01:32
He's also gotten his bonus.
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ื”ื•ื ื’ื ืงื™ื‘ืœ ื‘ื•ื ื•ืก.
01:34
The money seems to be burning a hole in his pocket.
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ื•ื ืจืื” ืฉื”ื›ืกืฃ ืฉื•ืจืฃ ื—ื•ืจ ื‘ื›ื™ืกื•.
01:37
Yes, Timmy, that's a nice car that will surely impress people.
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ื›ืŸ, ื˜ื™ืžื™, ื–ื• ืžื›ื•ื ื™ืช ื™ืคื” ืฉื‘ื˜ื•ื— ืชืจืฉื™ื ืื ืฉื™ื.
01:42
Oh! Looks like you're a little short.
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ืื•! ื ืจืื” ืฉื—ืกืจ ืœืš ืžืขื˜ ื›ืกืฃ.
01:45
Maybe you can follow Sheila's example.
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ืื•ืœื™ ืชื•ื›ืœ ืœืขืงื•ื‘ ืื—ืจื™ ื”ื“ื•ื’ืžื” ืฉืœ ืฉื™ืœื”.
01:47
You see, Timmy, just like Sheila,
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ืืชื” ืžื‘ื™ืŸ, ื˜ื™ืžื™, ื‘ื“ื™ื•ืง ื›ืžื• ืฉื™ืœื”,
01:49
after the first year, you'll have $11,000.
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ืื—ืจื™ ืฉื ื”, ื™ื”ื™ื• ืœืš $11,000.
01:52
But Timmy, that is still not enough to buy that fancy car.
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ืื‘ืœ ื˜ื™ืžื™, ื–ื” ืขื“ื™ื™ืŸ ืœื ืžืกืคื™ืง ื›ืกืฃ ื›ื“ื™ ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช ื”ืžืคื•ืืจืช ื”ื–ื•.
01:56
Why don't you leave the money deposited for another year?
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ืœืžื” ืฉืœื ืชืฉืื™ืจ ืืช ื”ื›ืกืฃ ืžื•ืคืงื“ ืœืขื•ื“ ืฉื ื”?
01:58
Let's see how your deposit will be doing in two years.
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ื‘ื•ืื• ื ืจืื” ืื™ืš ื”ืคื™ืงื“ื•ืŸ ื™ื”ื™ื” ื‘ืขื•ื“ ืฉื ืชื™ื™ื.
02:01
With a little bit of rearranging,
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ืขื ืžืขื˜ ืืจื’ื•ืŸ ืžื—ื“ืฉ,
02:03
it becomes the value of your money next year,
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ื–ื” ื™ื”ืคื•ืš ืœืขืจืš ืฉืœ ื”ื›ืกืฃ ืฉืœืš ื‘ืฉื ื” ื”ื‘ืื”,
02:05
times one plus the interest rate.
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ื›ืคื•ืœ ืื—ื“ ืคืœื•ืก ื’ื•ื‘ื” ื”ืจื™ื‘ื™ืช.
02:08
We can then convert the future value one year from now
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ืื ื—ื ื• ื™ื›ื•ืœื™ื ืื– ืœื”ืžื™ืจ ืืช ื”ืขืจืš ื”ืขืชื™ื“ื™ ืฉื ื” ืžืขื›ืฉื™ื•
02:11
to the present value times one plus the interest rate.
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ืœืขืจืš ื”ืขื›ืฉื•ื•ื™ ื›ืคื•ืœ ืื—ื“ ืคืœื•ืก ื’ื•ื‘ื” ื”ืจื™ื‘ื™ืช.
02:14
We can even simplify this further
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ืื ื—ื ื• ื™ื›ื•ืœื™ื ืืคื™ืœื• ืœืคืฉื˜ ืืช ื–ื” ื™ื•ืชืจ
02:15
by just squaring the value of one plus the interest rate.
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ืขืœ ื™ื“ื™ ืจื™ื‘ื•ืข ื”ืขืจืš ืฉืœ ืื—ื“ ืคืœื•ืก ื’ื•ื‘ื” ื”ืจื™ื‘ื™ืช.
02:19
Sorry, Timmy, you'll have more money after two years,
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ืžืฆื˜ืขืจื™ื ื˜ื™ืžื™, ื™ื”ื™ื” ืœืš ื™ื•ืชืจ ื›ืกืฃ ืื—ืจื™ ืฉื ืชื™ื™ื,
02:22
but you still can't afford the car!
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ืื‘ืœ ืขื“ื™ื™ืŸ ืœื ืชื•ื›ืœ ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช!
02:24
I don't know how many more years you'll have to wait,
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ืื ื™ ืœื ื™ื•ื“ืข ื›ืžื” ืฉื ื™ื ืขื•ื“ ืชืฆื˜ืจืš ืœื—ื›ื•ืช,
02:28
but I can tell you one way we can figure it out.
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ืื‘ืœ ืื ื™ ื™ื›ื•ืœ ืœืกืคืจ ืœืš ื“ืจืš ืื—ืช ื‘ื” ื ื•ื›ืœ ืœื“ืขืช.
02:30
Do you see that little number two in the equation?
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ืืชื” ืจื•ืื” ืืช ืžืกืคืจ ืฉืชื™ื™ื ื”ืงื˜ืŸ ื‘ื ื•ืกื—ื”?
02:33
Any number that you put in there
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ื›ืœ ืžืกืคืจ ืฉืชื•ื›ืœ ืœืฉื™ื ืฉื
02:34
is the number of years that you are waiting,
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ื”ื•ื ืžืกืคืจ ื”ืฉื ื™ื ืฉืชื—ื›ื”,
02:37
also known as the period.
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ืฉื™ื“ื•ืข ื’ื ื›ืชืงื•ืคื”.
02:39
Sure, Timmy, we can see how much you'll have in five years.
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ื‘ืจื•ืจ, ื˜ื™ืžื™, ืื ื—ื ื• ื™ื›ื•ืœื™ื ืœืจืื•ืช ื›ืžื” ื™ื”ื™ื” ืœืš ืขื•ื“ ื—ืžืฉ ืฉื ื™ื.
02:44
Let's connect future value and present value across five years.
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ื‘ื•ืื• ื ื—ื‘ืจ ืขืจืš ืขืชื™ื“ื™ ื•ืขืจืš ื ื•ื›ื—ื™ ืฉืœ ื—ืžืฉ ืฉื ื™ื.
02:48
Let's watch the period increase from two to five.
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ื‘ื•ืื• ื ืฆืคื” ื‘ืชืงื•ืคื” ื’ื“ืœื” ืžืฉื ืชื™ื™ื ืœื—ืžืฉ.
02:51
After 5 years, you'll have $16,105.10.
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ืื—ืจื™ 5 ืฉื ื™ื, ื™ื”ื™ื” ืœืš $16,105.10.
02:58
Sorry, Timmy, you have to wait a little longer.
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ืกืœื™ื—ื” ื˜ื™ืžื™, ืืชื” ืชืฆื˜ืจืš ืœื—ื›ื•ืช ืžืขื˜ ื™ื•ืชืจ.
03:01
10 years?
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10 ืฉื ื™ื?
03:02
Yeah! Let's see if you'll be able to buy the car then.
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ื›ืŸ! ื‘ื•ืื• ื ืจืื” ืื ืชื”ื™ื” ืžืกื•ื’ืœ ืœืงื ื•ืช ืืช ื”ืžื›ื•ื ื™ืช ืื–.
03:06
Not quite.
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ืœื ืžืžืฉ.
03:08
Well, Timmy, it looks like you'll need 26 years to afford this car.
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ื•ื‘ื›ืŸ ื˜ื™ืžื™, ื–ื” ื ืจืื” ื›ืื™ืœื• ืืชื” ืชืฆื˜ืจืš 26 ืฉื ื™ื ื›ื“ื™ ืœื”ืจืฉื•ืช ืœืขืฆืžืš ืืช ื”ืžื›ื•ื ื™ืช.
03:13
You should ask Sheila for a ride to the beach.
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ื›ื“ื™ ืฉืชื‘ืงืฉ ืžืฉื™ืœื” ื˜ืจืžืค ืœื—ื•ืฃ.
03:16
Maybe a bicycle will suit you better?
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ืื•ืœื™ ืื•ืคื ื™ื™ื ื™ืชืื™ืžื• ืœืš ื™ื•ืชืจ?
03:18
I hear the bus is pretty cheap!
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ืฉืžืขืชื™ ืฉื”ืื•ื˜ื•ื‘ื•ืก ื“ื™ ื–ื•ืœ!
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

https://forms.gle/WvT1wiN1qDtmnspy7