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swat32
3 years ago
5

A radioactive substance decays exponentially. A scientist begins with 190 milligrams of a radioactive

Mathematics
1 answer:
worty [1.4K]3 years ago
6 0

Answer: 65.1 (mg)

Step-by-step explanation:

y=190*e^{-a*t}\\\\Calculate\ a:\\\\t=33,y=95(mg)\\\\190*e^{-a*33}=95\\\\e^{-a*33}=0.5\\\\-a*33=ln(0.5)\\\\a=\dfrac{ln(\dfrac{1}{2}) }{-33} \\\\a=0,02100... \approx{0.021}\\\\If\ t=51\ h, y=190*e^{-0.02100*51}=65.09167...\approx{65.1}

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-2x^2+5x-4=0 , find the discriminant
BaLLatris [955]

Answer:

The discriminant is -7

Step-by-step explanation:

The discriminant of a quadratic function/equation(ax^2+bx+c = 0) is calculated as:

b^2 -4ac

Here

b is the co-efficient of x

a is the co-efficient of x^2

and c is the constant

Given equation is:

-2x^2+5x-4=0

Here

a = -2

b = 5

c = -4

Putting the values in the formula for discriminant

= b^2 - 4ac\\= (5)^2 - 4(-2)(-4)\\= 25 - 32\\=-7

As the discriminant is negative, the equation has no real solution.

Hence,

The discriminant is -7

5 0
3 years ago
Can I get some help with 1) plz
erik [133]
Your answer is 12 because 8*4=24 and 3*4=12                                                                                                                                                                                                                 Your answer is 12
6 0
4 years ago
Read 2 more answers
Jenna flips two pennies 105 times how many times can she expect those coins to come up heads
alukav5142 [94]
The more observations you make the closer and closer the experimental probability will approach the theoretical probability.  In this case the theoretical probability is:

P(HH)=(1/2)(1/2)=1/4

So in 105 trials one would expect to get two heads:

105(1/4)=26.25 times.
7 0
3 years ago
Someone please help!
erastova [34]

Answer:

  • k = 6.26

Step-by-step explanation:

Find the midpoint of each frequency range, multiply that number by the frequency, sum up and divide by the total frequency.

This will give the mean number.

<u>The mean is:</u>

  • [17*( 3 + 3.5)/2 + 21*(3.5 + k)/2 + 33*(k + 4)/2 + 54*(4 + 4.5)/2 + 15*(4.5 + 6)/2]/140 = 4.09
  • 55.25 + 10.5k + 36.75 + 16.5k + 66 + 229.5 + 78.75 = 140*4.09
  • 17k + 466.25 = 572.6
  • 17k = 572.6 - 466.25
  • 17k = 106.35
  • k = 106.35/17
  • k = 6.26

Note, I expected the value of k between 3.5 and 4. This is a bit of illogical outcome.

8 0
3 years ago
What is the simplified form of 15x^5/20y^6*6y^4/5x^2
Ainat [17]

Answer:

The simplified form of the equation is 9x^3/10y^2   Good Luck!

Step-by-step explanation:


4 0
3 years ago
Read 2 more answers
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