Friday, August 10, 2007

Help! Where did the $1 go?

Ah boy wants to buy a pair of $97 pants, he asks his parents for the money. His mom & dad each gave him $50($50+$50=$100). So he bought the pants and got back $3 change. He decided to keep $1 and return $1 to his dad and mom, therefore, they end up paying $49 each($50-$1=$49).

$49+$49+$1=$99

Where did the $1 go???

8 comments:

Princess Winnilicious said...

I thought he kept $1?

阿陈 said...

Haha it is actually a fake impression that the parents actually spend $49.

Below is the explanation:

$97 ($48.50 X 2)
$3 ($1 X 3)

So if you were to addup $48.50 and $1, the parents actually spend a total of $49.50.

The fake impression here is when people actually thought that since Ah Boy give back $1 each, the parents each actually give $49 to Ah Boy. Does this help u find the missing $1?

Pubed said...

No fun la.. Chiu posted the answers too early. :)

KeV's wAlKAbOuT said...

Another explanation I think:

Mum lend $50
Dad lend $50
So after returning $1 each to both,
each in effect lends only $49.

So in total they lend $49x2=$98

and the pants only cost $97, so $98-$97 = $1 which is what ah boy kept for himself! Solved!

Brinjal said...

I Like Kev's explanation :D.

But isn't it amazing how math works (and in this case doesn't). No wonder some kids can get really confused!

http://www.entrepreneur.com.sg

Dan said...

mom gives $50

50 +

dad gives $50

50 + 50 +

ah boy returns $1 each

(49+1) + (49+1) +

ah boy keeps $1

49+1 + 49+1 + 1

rearranging:

49+49+1+1+1 = 100

the trick is that "$49+$49+$1" is wrong.

Dan said...

oh wow, instead of solving the problem, i made a new one!

eh, but the idea is there, i think.

Anonymous said...

Listened up guys..in mathemetics, its a problem of not using BODMAS...thats all

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