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ddd [48]
3 years ago
15

In an over-fished area, the catch of a certain fish is decreasing exponentially.? Use k=0.084 to determine how long will it take

for the catch to reach half of its current amount?
Mathematics
1 answer:
kvv77 [185]3 years ago
5 0
The answer is 8.25 years

The exponential function can be expressed as:
A = P * e^(kt)
A - the final amount
P - the current amount
k - the rate
t - time in years

If the final amount is the half of its current amount, then:
A = P/2

So, 
A = P * e^(kt)
P/2 = P * e^(kt)

Divide P from both sides:
1/2 = e^(kt)

Logarithm both sides with natural logarithm:
ln(1/2) = ln(e^(kt))
ln(0.5) = kt * ln(e)

k = -0.084
-0.693 = -0.084 * t * 1
-0.693 = -0.084t
t = -0.693 / -0.084
t = 8.25 years

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Under certain conditions, the number of bacteria present in a colony is approximated by f(t) = Age 0.023t, where t is in minutes
AleksandrR [38]

Answer:

  • 5 min: 3,029,058
  • 10 min: 3,398,220
  • 60 min: 10,732,234

Step-by-step explanation:

The given function is evaluated by substituting the given values of t. This requires using the exponential function of your calculator with a base of 'e'. Many calculators have that value built in, or have an e^x function (often associated with the Ln function).

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<h3>5 minutes</h3>

The number of bacteria present after 5 minutes is about ...

  f(5) = 2.7×10^6×e^(0.023×5) ≈ 3,029,058

<h3>10 minutes</h3>

The number of bacteria present after 10 minutes is about ...

  f(10) = 2.7×10^6×e^(0.023×10) ≈ 3,398,220

<h3>60 minutes</h3>

The number of bacteria present after 60 minutes is about ...

  f(60) = 2.7×10^6×e^(0.023×60) ≈ 10,732,234

8 0
2 years ago
Which is the best estimate for this<br><br> 4/5% of 192
slavikrds [6]
When you are looking for a fraction, it is best to convert this into a percentage, which in this case, is 80%. Following on from this, you will have to round the number up, which in this case, will be to 200- however, depending on the number, this could be different. From this, you then have to find 80% of 200. From this, you then have to divide 200 by 10, giving you 20, and then multiply this by 8, to get 160, and this is a good estimate for 4/5 of 192. Hope this helps you <span />
7 0
3 years ago
Read 2 more answers
42 less than the product of 28 and an unknown number is 154
zalisa [80]
First you write out your equation, which is 28x-42=154. Then you solve you equation. First, add 42 to each side, get 28x=196. Divide both sides by 28, get x=7.
8 0
3 years ago
A ships triangular signal flag has a base of 8 inches and an area of 64 square inches. What is the height of the signal flag
Firlakuza [10]
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3 years ago
A right triangle has one side that measures 4in. The angle opposite that side measures 80 degrees. What is the length of the hyp
Crazy boy [7]

Hello from MrBillDoesMath!

Answer:

4/sin(80)

which is approximately 4.06



Discussion:

From the triangle, not drawn too accurately  (see attachment)


sin(80) = side opposite /hypotenuse   =>

sin (80) =  4/c            =>       multiply both sides by "c"

c sin(80) = 4/c * c      =>      

c sin(80) = 4               =>      divide both sides by sin(80)

c = 4/sin(80)

and 4/sin(80) is approximately 4.06


Thank you,

MrB

6 0
3 years ago
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