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tresset_1 [31]
3 years ago
12

Iodine-131, a radioactive substance that is effective in locating brain​ tumors, has a​ half-life of only eight days. a hospital

purchased 22 grams of the substance but had to wait seven days before it could be used. how much of the substance was left after seven ​days?
Mathematics
1 answer:
Ad libitum [116K]3 years ago
7 0
5 days/8 days = 0.625 half lives 

<span>fraction left after 0.625 half lives = (1/2)^0.625 </span>

<span>= 0.6484197773 </span>

<span>Amount left = 20*0.6484197773 gms </span>

<span>= 12.97 gms to dp <<<</span>
You might be interested in
Given that r=(9,8,3),v=(6,7,-1)and w=(-3,3,7), evaluate (r+v) w
lakkis [162]

Answer:

(-45,45,14)

Step-by-step explanation:

(r+v)*w=((9,8,3)+(6,7,-1))*(-3,3,7)=(15,15,2)*(-3,3,7)=(-45,45,14)

Does this help (I'm not sure of the rightness of this answer), if it did, please mark brainliest

4 0
3 years ago
Need help please ! parallelogram
OverLord2011 [107]

Answer:

11). m∠W = 70°

12). m∠M = 95°

13). m∠Q = 135°

14). m∠Q = 55°

15). m∠X = 110°

Step-by-step explanation:

11). m∠W + m∠X = 180° [Consecutive interior angles]

    (24x - 2) + (36x + 2) = 180°

     60x = 180°

     x = \frac{180}{60}

     x = 3

     Therefore, m∠W = (24x - 2)°

     m∠W = (24×3 - 2)

               = 72 - 2

               = 70°

     Since opposite angles of a parallelogram are equal in measure.

     m∠Y = m∠W = 70°

12). m∠J + m∠K = 180° [Consecutive interior angles]

     (6x + 19) + (8x + 7) = 180°

     14x + 26 = 180

     14x = 180 - 26

     14x = 154

     x = \frac{154}{14}

     x = 11

     m∠K = (8x + 7)

     m∠K = 8×11 + 7

     m∠K = 95°

     Since m∠M = m∠K

     Therefore, m∠M = 95°

13). m∠Q = m∠S [Opposite angles of a parallelogram]

      x + 135 = 2x + 135

      2x - x = 0

      x = 0

      Therefore, m∠Q = 135°

14). m∠Q = m∠S [Opposite angles of a parallelogram]

      14x - 1 = 13x + 3

      14x - 13x = 3 + 1

      x = 4

      m∠Q = (13x + 3)

                = 13×4 + 3

                = 52 + 3

      m∠Q = 55°

15). m∠Z = m∠X

     (19x - 4) = (17x + 8)

      19x - 17x = 12

      2x = 12

      x = 6

      m∠X = (17x + 8)°

      m∠X = 17×6 + 8

      m∠X = 110°

5 0
2 years ago
Aljan and Bella are both driving from Cleveland to Chicago. Aljan leaves at
Natalija [7]

Answer:

Bella will pass Ajjan after 4h and they will have travelled 260 miles.

Step-by-step explanation:

In order to calculate the number of hours, "x", that it'll take for Bella to pass Aljan, we need to find the value of "x" that makes both equations equal. Therefore,

60*x + 20 = 65*x\\65*x - 60*x = 20\\5*x = 20\\x = \frac{20}{5} = 4

In order to calculate the distance they traveled, we must use this value for "x" in any of the equations, as done below:

y = 65*4\\y = 260

Bella will pass Ajjan after 4h and they will have travelled 260 miles.

4 0
2 years ago
a system of equations is shown below: equation a: 2c = d − 8 equation b: c = 3d 8 which of the following steps should be perform
Fofino [41]
If you would like to know which of the following steps should be performed to eliminate variable d first, you can find this using the following steps:

equation a: 2c = d - 8      /*(-3)
equation b: c = 3d + 8
__________________
-6c = -3d + 24
c = 3d + 8
__________________
-6c + c = -3d + 24 + 3d + 8
-5c = 32
5c = -32
c = -32/5

<span>The correct result would </span>be: <span>multiply equation a by −3.</span>
3 0
3 years ago
What is the least value of x which the inequality is true? 16 is greater than or equal to -2x
tia_tia [17]

Answer:Then the system of inequalities that represents the graph is second option:

2x +y is less than or equal to 3, and y-x is greater than or equal to 2

Step-by-step explanation: The area shaded is below the blue line and above the red line.

1.) The blue line goes through the points:

P1=(0,3)=(x1,y1)→x1=0, y1=3

P2=(1,1)=(x2,y2)→x2=1, y2=1

Slope: m=(y2-y1)/(x2-x1)

m=(1-3)/(1-0)→m=(-2)/(1)→m=-2

Point-slope form:

y-y1=m(x-x1)

y-3=-2(x-0)→y-3=-2(x)→y-3=-2x→y-3+3=-2x+3→y=-2x+3

The area below the blue line is:

y<=-2x+3→y+2x<=-2x+3→2x+y<=3

2x +y is less than or equal to 3

2.) The red line goes through the points:

P1=(0,2)=(x1,y1)→x1=0, y1=2

P2=(-2,0)=(x2,y2)→x2=-2, y2=0

Slope: m=(y2-y1)/(x2-x1)

m=(0-2)/(-2-0)→m=(-2)/(-2)→m=1

Point-slope form:

y-y1=m(x-x1)

y-2=1(x-0)→y-2=1(x)→y-2=x→y-2+2=x+2→y=x+2

The area above the red line is:

y>=x+2→y-x>=x+2-x→y-x>=2

y-x is greater than or equal to 2

Then the system of inequalities that represents the graph is:

2x +y is less than or equal to 3, and y-x is greater than or equal to 2

Read more on Brainly.com - brainly.com/question/11890005#readmore

6 0
3 years ago
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