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Ahat [919]
3 years ago
11

Suppose an unknown radioactive substance produces 12800 counts per minute on a Geiger counter at a certain time, and only 800 co

unts per minute 10 days later. Assuming that the amount of radioactive substance is proportional to the number of counts per minute, determine the half-life of the radioactive substance.
Mathematics
1 answer:
suter [353]3 years ago
5 0

Answer:

2.5 days.

Step-by-step explanation:

The number of half lives  is n where

12800(0.5)^n = 800

12800(0.5)^4 = 800

so n = 4

So the half life is 10/4

= 2.5 days.

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PLEASE HELP ME!
elena55 [62]

Answer:

hello :

f(x) = -x+0.25

g(x) = x²+3x+2

ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ

f(-3.5) = 3.75

g(-3.5) = 3.75

ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ

f(-0.5) =0.75

g(-0.5) = 0.75

ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ

conclusion : answer : A) x = −3.5 and x = −0.5 

Step-by-step explanation:

Hope this helps:)

3 0
3 years ago
Read 2 more answers
Tim sold half of his comic books then bought 8 more. He now has 17. How many did he start with?
disa [49]

Answer:

18

Step-by-step explanation:

18 divided by 2 is 9 plus 8 is 17

7 0
3 years ago
The height, h of a baseball, in meters at t seconds after it is tossed out of a window
Vadim26 [7]

You'll be solving:

-5t^2 + 20t + 15 = 3t + 3

5t^2 - 17t - 12 = 0

(t - 4)(5t + 3) = 0

t = 4 or t = -3/5, but let's assume t ≥ 0

Step-by-step explanation:

4 0
2 years ago
The ray XZ is the angle bisector of ∠WXY and m∠WXY = 145°. Enter m∠WXZ. The measure of ∠WXZ is
Ganezh [65]

Answer:

72.5°

Step-by-step explanation:

Since, the ray XZ is the angle bisector of ∠WXY.

\therefore m\angle WXZ = \frac{1}{2} \times m\angle WXY\\\\\therefore m\angle WXZ = \frac{1}{2} \times 145\degree \\\\\therefore m\angle WXZ =72.5\degree \\

6 0
4 years ago
1200$ invested at a rate of 3.5% compounded quarterly; 4 years
Tju [1.3M]

Step-by-step explanation:

<em>1st year</em>:

(1200 x 3.5 x 1) ÷ 100 = $42

<em>2nd year:</em>

(1242 x 3.5 x 1) ÷ 100= $43.47

<em>3rd year:</em>

(1285.47 x 3.5 x 1) ÷ 100= $44.99≈ $45

<em>4th year:</em>

(1330.47 x 3.5 x 1) ÷ 100= $46.56

Compound interest:

$(42 + 43.47 + 45 + 46.56)

=<u>$ 177.03</u>

4 0
3 years ago
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