Åk 6–9
 
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3.4 More than 100 percent 
We have learned that 100 is the same thing as ”the whole”.  Can something be more than 100 percent? Below we follow an example of how the price of milk as changed in Sweden.

In 1965, a liter of milk cost 1 kr.

In 1980, a liter of milk cost 2 kr.

Foto: Fredrik Enander

The price of milk has doubles from 1965 to 1980.  How many percent has the price risen by?  The original value of 1 kr is equivalent to 100 percent.  The price has then increased by 1 kr and because 1 kr is equivalent to 100 percent then the increase is also 100 percent.  So:




You can calculate this in the following way:

Change in value: 2 kr - 1 kr = 1 kr
Original value: 1 kr



The calculation in the example above would look like this:

1 kr

1 kr
= 100 %




In 1965, a liter of milk cost 1 kr.

In 1988, a liter of milk cost 5 kr.

Foto: Fredrik Enander


The original price is like before 1 kr.  The increase between these years is 5 kr – 1 kr = 4 kr. If 1 kr is 100 percent, then 4 kr should be 400 percent.  We can test our calculations according the formula above.

4 kr

1 kr
= 400 %

It seems that the calculations agree with what we thought and the price has indeed increased by 400 percent between 1965 and 1988.




 

The American magazine The Economist has since 1986 used the Big Mac hamburger to estimate a country’s price levels.

The table shows price development in Sweden between 1986 and 2008.


By how many percent has the price of a Big Mac increase between the years 1986 and 2008?

The original value, in other words the price in 1986: 16.50
The change: 38.00 kr – 16.50 kr = 21.50 kr

The change in percent = 21.50 kr

16.50 kr
1.30 = 130 %

The price of a Big Mac has increased by 130 % between 1986 and 2008.




In 1950, 1 kr of eggs cost 3.41 kr, and in 2006, the price had risen by 529.4 %.