Original subtitles

Instructor: Hello, again.

This is going to be a short lecture

where we introduce a new type of combinations.

Sometimes, a combination can be a mixture

of different smaller individual events.

Imagine the following scenario.

The diner near work just introduced a lunch menu,

which consists of a sandwich, a drink and a side.

Assuming you go there every day,

how long will it take for you to be able to try out

every possible item on the menu?

To solve this, you need to know what is included

in their lunch deal.

Each menu consists of a sandwich, a side and a drink.

They offer three types of sandwiches;

a panini, a Philly cheesesteak and a veggie wrap.

The sides they have available

are only fries and onion rings,

and the drinks they offer are cola or water.

The way to tackle such problems

is by thinking about the different parts of the menu

as separate positions.

If we start by choosing a sandwich first,

we have three options.

For each of them, we can pick one of two sides;

fries or rings.

To complete our menu, we would also have to add a drink,

which can either be water or coke.

Therefore, for any combination of sandwich and side,

we have two ways of completing the menu.

Thus, we would have a total of three dishes,

times two sides, times two drinks,

or 12 different lunch menus at the diner.

That wasn't that hard, was it?

Good.

In online marketing,

you often need to try out several versions of an online ad

before you decide which one is the best.

Imagine you're using Facebook's promotional advertisements.

Your ad consists of four parts;

a heading, a thumbnail, a post description,

and a clickable button.

Now, you have three different headings,

five thumbnails, three post descriptions and two buttons.

How many different ads would you have to generate

to make sure you've tried all possibilities?

Using the method we showed earlier,

that would require you to test out three,

times five, times three, times two, equals 90 different ads.

This is important because it shows us

how many different possibilities there are,

despite the choices for each part seeming limited.

Furthermore, this allows project managers

to determine the appropriate amount of time it would take

for such a task to be completed.

When the components are simply too many,

they can flat out remove several of the options

to tremendously decrease the workload.

Good job everyone.

The way of calculating the total number of combinations

for these kinds of questions

is by simply multiplying the number of options available

for each individual event.

See you in the next video.