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1+1==2？

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Type A

1 1+1=1

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Developing photos 1+1=1

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Type B

1 1+1=1.5

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MacDonald: The second cup half price ！

23/4/11

height=11.5cmradius=3.3cm

• If we confirmed the volume• then what kind of proportion can

minimise the superficial area?

23/4/11

Volume & Superficial area

214.3 hrV

rhrS 28.628.6 2

23/4/11

Confirming the volume

• then the superficial area

• when h=r ,we get the minimum of S.• So the cost of material will be least.

)22

(14.3 2min rh

hrS

23/4/11

BUT....

• h=11.5cm• r=3.3cm• This will waste about30% material

• why?

23/4/11

• It is more like a fish can ,right?

23/4/11

Reason

• Customers may misleading by horizontal-vertical illusion .

• which one you thinka little bit longer?

23/4/11

So,this is the real reason why factory produ

ce the container like this, which as we can see today on the supermarket. Customers are more likely to buy the longer one. Even if they know they are the same, or the shorter one can contain more than the longer one.

Why does milk come in rectangular containers?

Round container?

Why soft drinks come in round cans?

One possibility

soft drinks are often consumed directly from the container, the extra cost of strong cylindrical containers is justified because they fit more comfortably in the hand…

Milk comes in rectangular containers, while soft drinks come in round cans?

What makes the different?

But even if most people drank milk straight from the carton, the cost-benefit principle suggests that it would

be unlikely to be sold in cylindrical containers.

Most soft drinks in supermarkets are stored in open shelves, which are cheap to buy and have no operating costs.

Milk is exclusively stored in refrigerated cabinets, which are both expensive to purchase and costly to operate.

What’s more?