Question

how does the number of bacteria change over time? choose 1 answer: a the number of bacteria decreases by 20% each hour. b the number of bacteria increases by 20% each hour. c the number of bacteria decreases by 40% each hour. d the number of bacteria increases by 40% each hour.

Explanation:

Step1: Observe the graph trend

The graph shows an upward - sloping line, so the number of bacteria is increasing over time.

Step2: Estimate the growth rate

At time \(t = 0\), the number of bacteria is approximately \(50\). At \(t = 1\), it is around \(60\). The growth from \(50\) to \(60\) is \(\frac{60 - 50}{50}\times100\%=\frac{10}{50}\times 100\% = 20\%\).

Answer:

B. The number of bacteria increases by 20% each hour.