A because the square is in the (10) place and the circle is in the (1) place and 10 is 10 times bigger than 1
90+55+75+60+80+90=450
450/6=75
Answer:
- <u>Question 1:</u>
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- <u>Question 2:</u>
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- <u>Question 3:</u>
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- <u>Question 4:</u>
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Explanation:
<u>Question 1: Write down the differential equation the mass of the bacteria, m, satisfies: m′= .2m</u>
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a) By definition: 
b) Given: 
c) By substitution: 
<u>Question 2: Find the general solution of this equation. Use A as a constant of integration.</u>
a) <u>Separate variables</u>

b)<u> Integrate</u>


c) <u>Antilogarithm</u>



<u>Question 3. Which particular solution matches the additional information?</u>
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Use the measured rate of 4 grams per hour after 3 hours

First, find the mass at t = 3 hours

Now substitute in the general solution of the differential equation, to find A:

Round A to 1 significant figure:
<u>Particular solution:</u>

<u>Question 4. What was the mass of the bacteria at time =0?</u>
Substitute t = 0 in the equation of the particular solution:

2a+4(7+5a)
Distribute 4 into 7 and 5a
2a+28+20a
Combine like terms
Final Answer: 22a+28