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Stella [2.4K]
3 years ago
12

A colony of bacteria is growing exponentially according to the function below, where t is in hours. About how many hours will it

take for the population to reach 400?
Mathematics
1 answer:
Ivenika [448]3 years ago
4 0
The function is:
B ( t ) = 4 * e^(0.8 t)
4 * e^(0.8 t) = 400
e^(0.8 t) = 400: 4
e^(0.8 t) = 100   / ln
ln e^(0.8 t) = ln 100  ( and since: ln e = 1 and ln e^x = x * ln e )
0.8 t = 4.6
t = 4.6 : 0.8 = 5.76 ≈ 6
Answer:
D ) 6 hours.
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The height h in feet of a ball thrown vertically upward from the top of a 288-foot tall building is given by h=288+48t-16t^2 whe
mr Goodwill [35]

6 sec can take penny to strike the ground.

Solution:

Given data:

H_0=288 feet

V_0=48 feet

h(t)=288+48t-16t^2

Re-arrange the terms from greatest degree to smallest degree.

h(t)=-16t^2+48t+288

We can solve it by applying quadratic formula,

$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}

Here a = –16, b = 48, c = 288

$t=\frac{-48\pm \sqrt{48^2-4(-16)(288)}}{2(-16)}

$t=\frac{-48\pm \sqrt{2304+18432}}{-32}

$t=\frac{-48\pm \sqrt{20736}}{-32}

$t=\frac{-48\pm144}{-32}

Now, write find two t's using plus and minus operation.

$t=\frac{-48+144}{-32},\ \ t=\frac{-48-144}{-32}

$t=\frac{96}{-32},\ \ t=\frac{-192}{-32}

t = –3 (or)   t = 6

We cannot write time is negative. so neglect t = –3.

Therefore t = 6.

Hence 6 sec can take penny to strike the ground.

8 0
2 years ago
For which operations is the set {0, 1} closed?
velikii [3]
0 × <span>0 = 0
0 </span>× <span>1 = 0
1 </span>× <span>1 = 1

Which means multiplication is closed under {0, 1}

</span><span>1 </span>÷ <span>1 = 1
0 </span>÷ <span>1 = 0
</span>
Division is not closed under {0, 1}

1 + 1 = 2

Addition is not closed under {0, 1}

0 - 1 = -1

Subtraction is not closed under {0, 1} either



So it's only A. Multiplication which is closed under {0, 1}
5 0
3 years ago
Allison had 18 postage stamps she gave 2/9 of the stamps to her mother and used 1/2 of the remaining stamps to send letters to h
Travka [436]
So first you have to do 18 multiply by 2/9. This gets you 4, next you multiply by 1/2. This gets you 2.

ANSWER: She will have 2 stamps left.
5 0
2 years ago
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Thepotemich [5.8K]

Answer:

A,D

Step-by-step explantion

A,d

6 0
3 years ago
eric is making a dress. the design calls for a right triangular piece of material. if the second angle has to be 35% what is the
svet-max [94.6K]
U have a right triangle...so one angle is 90%......and the second angle is 35%...keep in mind, the angles of a triangle = 180%
so the measure of the third angle is : 180 - 90 - 35 = 55%
3 0
3 years ago
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