numerical: epidemic growth

Question

An infection doubles its case count every 3 days. Starting with 400 cases, how many after 9 days assuming ideal doubling?

RankGuru · Accepted Answer

1. **Identify Number of Intervals**: 
   - Total time = 9 days.
   - Doubling time = 3 days.
   - Number of doublings ($n$) = $\frac{Total \ time}{Doubling \ time} = \frac{9}{3} = 3$.
2. **Apply Growth Formula**: 
   - $Final \ count = Initial \ count 	imes 2^n$
   - $Final \ count = 400 	imes 2^3 = 400 	imes 8 = 3200$.
3. **Manual Check**: 
   - Start: 400
   - Day 3: 800
   - Day 6: 1600
   - Day 9: 3200.

Rank Guru

numerical: epidemic growth

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