Exponential growth and decay
Evaluate an exponential growth/decay model A = A0(1 +- p/100)^t for a whole-number result. Unlimited questions, five difficulty levels, and a full worked solution every time — free.
Try one
Right now the number of bacteria in a petri dish is 500. It grows by 10% every year. About how many will there be after 1 year?
A = 500(1 + 10100)1
Answer: 550
See one solved, step by step
Right now the number of bacteria in a petri dish is 400. It grows by 8% every year. About how many will there be after 3 years?
A = 400(1 + 8100)3
📘 Worked solution
1Growth factor: 1 + 0.08 = 1.08growing by 8% means the new amount is (1 + 8/100) times the old amount.
2A = 400 · 1.083 = 503.88Apply that factor once per year — that's why it's raised to the power 3.
3~ 504Round to the nearest whole number — you can't have part of one.
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