Math CentralQuandaries & Queries


Question from Kyle, a student:

I need help finding out this question:
40 meters increased by 20%
Is the answer 800 or is it 8?

Hi Kyle,

100% of 40 meters is 40 meters so an increasing 40 meters by 100% would give you $40 + 40 = 80$ meters. Thus increasing 40 meters by 20% couldn't be 800 meters.

20% is $\large \frac{20}{100}$ so if you increase 40 meters by 20% you obtain an increase of $\large \frac{20}{100} \normalsize \times 40$ meters.


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