Compund Interest 2

Test yourself

Compound Interest

In summer, the number of ants in a colony increases by 20% each day. On the first day, there are 10,000 ants. How many days until the colony numbers more than 30,000?

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The formula for compound interest

  • N is the number of ants
  • n is the number of days passed
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  • This is the first day we are over 30 000 so the answer is 7 days.

Jump to other topics


1.1Place Value

1.2Factors & Multiples


1.4Fractions, Decimals & Percentages

1.5Growth & Decay

1.6Measurements & Units



3Ratio, Proportion & Rates of Change

4Geometry & Measures



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