Tuesday, September 04, 2007

One per cent

Recent stuff was about words. I am a marketing consultant, but I mainly work with numbers, and I believe in things that can be measured. Sometimes those things may initially appear unpalatable. But with just a few seconds of thought, it should all be obvious.

I'll keep the numbers round and simple. Imagine that you got a large basket of 100 kilos of fresh organic fruit delivered to your door while you were out.

Obviously fruits left outside will slowly shrivel as water evaporates. By the time that you got home, let's assume that the proportion of water has dropped from 99 percent to 98 percent

So, very approximately, how much does the basket of fruit now weigh? About 98 kilos?


Does your common sense tell you that the answer is only 50 kilos?


Ann said...


I'm clearly missing something. How heavy is the basket without the fruit?

RNB said...

There is no twist here. The weight of the basket is completely irrelevant.

But this is not a game. I'm not trying to trick anyone. There is no "lateral thinking" required. I've given the answer. It is just very simple maths.

I'm just showing (like I often have to do at work:) that even very simple maths does not always give answers that align with "intuition".

Ann said...

You see my maths and common sense are in alignment. Hence uh.

Faisal said...
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Faisal said...
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Faisal said...

I don't get it. Supposedly 50 kilos of water has evaporated, out of a total beginning weight of 100 kg. This somehow decreases the proportion of water content by 1%???

Please explain the maths.

RNB said...

You do get it. There is nothing else to say. Yes, the proportion of water has dropped from 99% to 98%. Yes the "dry weight" proportion has increased from 1% to 2%. Yes the total weight has decreased by 50 kg.

Those were always the facts. I was never trying to hide anything or trick you. I was just trying to show that in some cases, for some people, initial intuition does not always match the facts.

Faisal said...

Well, it's not worded very well then. If the overall weight loss of 50kg is completely separate from the percentage water composition, then why try to relate them, or imply a relationship in the wording? Of course it would throw off your interpretation.

Usually, intuition or instinct are excellent survival mechanisms. They should not be suppressed, unless they consistently lead to incorrect conclusions.

If you state it as follows, intuition will be in alignment with fact:
100 kg of fruits lose 50kg of their weight due to water evaporation. Originally, 99% of the fruits' weight was water. Now, they consist of 98% water.

It's just tricky wording, intentionally misleading our intuition. Bah.