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39 votes
The number of bacteria in a colony growing exponentially. At 4 pm yesterday the number of bacteria is 400.And at 6 pm yesterday it was 3600. How many bacteria in the colony at 7 pm?

User Shakil Ahmed
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2 Answers

13 votes
13 votes

Answer:

10800

Explanation:

4 PM: 400

5 PM: 1200

6 PM: 3600

it multiplies by 3, so the answer is 10800

User Maytal
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2.8k points
7 votes
7 votes

Answer:

10800

Explanation:

The number of bacteria in a colony growing exponentially. At 4 pm yesterday the number of bacteria is 400.And at 6 pm yesterday it was 3600. How many bacteria in the colony at 7 pm?

Explanation:

B = B₀ Kⁿ

At 4 pm yesterday the number of bacteria is 400

B₀ = 400

n = number of hrs

at 6 pm yesterday it was 3600 => n = 6- 4 = 2 hrs

B₂ = 3600

=> 3600 = 400 * k²

=> k² = 9

=> k = 3

At 7 Pm Yesterday

n = 7-4 = 3

B₃ = 400 * 3³

=> B₃ = 27 * 400

=> B₃ = 10800

bacteria in the colony at 7 pm = 10800

or B₂ = 3600 & n = 7-6 = 1

Then B₃ = 3600 * 3¹ = 10800

And boom here

User Mark Bowker
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2.9k points