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3 years ago

Strontium 90 is a radioactive material that decays according to the function

Mathematics

2 answers:

Julli [10]3 years ago

5 0

Answer:

decay rate is 2.44% per year

after 40 years, 400*(e^-0.976)=150.73 gm

300=400(e^-0.0244t)

0.75=e^-0.0244t

ln both sides

-0.2877=-0.0244t

t=11.79 years

t (1/2) occurs when ln(0.5)=-0.0244t

t=28.41 years

Have a nice day!

kifflom [539]3 years ago

3 0

Answer:

hey mate

the time required is 28.41 days

You might be interested in

What transformation rule would represent a shift of 3 units to the left 4 units down?

Llana [10]

Given:

Shift of 3 units to the left 4 units down.

To find:

The transformation rule.

Solution:

The rule of transformation is

$(x,y)\to (x+a,y+b)$ ...(i)

Here, a<0 if the figure shifts a units left and a>0 if the figure shifts a units right.

Similarly, b<0 if the figure shifts b units down and b>0 if the figure shifts b units up.

If a transformation represents shift of 3 units to the left 4 units down, then a=-3 and b=-4.

Putting a=-3 and b=-4 (i), we get

$(x,y)\to (x+(-3),y+(-4))$

$(x,y)\to (x-3,y-4)$

Therefore, the correct option is B.

4 0

3 years ago

NEED HELP ASAP PLEASE

olga nikolaevna [1]

Answers:

interest = $75
balance at maturity = $3075

=============================================================

Explanation:

The simple interest formula is

i = p*r*t

where in this case,

p = 3000 = principal (amount deposited)
r = 0.10 = annual interest rate in decimal form
t = 3/12 = 0.25 = number of years

So,

i = p*r*t

i = 3000*0.10*0.25

i = 75 is the amount of interest earned

This adds onto the initial deposit to get the final balance when the CD matures (ie when you're able to withdraw the money without penalties)

The balance at maturity is p+i = 3000+75 = 3075 dollars

---------------

In short, you deposit $3000 into the CD and have to wait 3 months for the amount to update to $3075.

7 0

3 years ago

Please help me!! Will get brainliest!

makvit [3.9K]

Completing the square follows the principle of taking $a x^{2} +bx+c$ and converting it into $(x+ \frac{b}{2})^2+d$ where d is the 'correctional number' as I like to call it - i.e. the number that converts the expanded bracket into the +c, since the expanded bracket will give us $a x^{2} +b$ .

In this case, 2/2=1 so we have the first part: $(w+1)^2$ .
Expanding this gives us $w^2+2w+1$ . We need c to be 9, so we can just add 8.
Putting this together:

$w^2+2w+9=(w+1)^2+8$

Now we can solve it more easily.
Rearranging:
$(w+1)^2=-8 \\ w+1= +-\sqrt{-8} = +-\sqrt{8}i=+-2 \sqrt{2}i \\ \boxed{w=-1+ 2\sqrt{2}i\ or\ -1-2 \sqrt{2}i }$

5 0

3 years ago

Graph h(x)=-x^4 +3

Katyanochek1 [597]

Hope this helps, the y intercept is 3 ans the x intercepts are +1.3 and -1.3

8 0

3 years ago

Suppose we write down the smallest positive 2-digit, 3-digit, and 4-digit multiples of 9,8 and 7(separate number sum for each mu

jok3333 [9.3K]

Answer:

Sum of 2 digit = 48

Sum of 3 digit = 317

Sum of 4 digit = 3009

Total = 3374

Step-by-step explanation:

Given:

9, 8 and 7

Required

Sum of Multiples

The first step is to list out the multiples of each number

9:- 9,18,....,99,108,117,................,999

,1008

,1017....

8:- 8,16........,96,104,...............,992,1000,1008....

7:- 7,14,........,98,105,.............,994,1001,1008.....

Calculating the sum of smallest 2 digit multiple of 9, 8 and 7

The smallest positive 2 digit multiple of:

- 9 is 18

- 8 is 16

- 7 is 14

Sum = 18 + 16 + 14

Sum = 48

Calculating the sum of smallest 3 digit multiple of 9, 8 and 7

The smallest positive 3 digit multiple of:

- 9 is 108

- 8 is 104

- 7 is 105

Sum = 108 + 104 + 105

Sum = 317

Calculating the sum of smallest 4 digit multiple of 9, 8 and 7

The smallest positive 4 digit multiple of:

- 9 is 1008

- 8 is 1000

- 7 is 1001

Sum = 1008 + 1000 + 1001

Sum = 3009

Sum of All = Sum of 2 digit + Sum of 3 digit + Sum of 4 digit

Sum of All = 48 + 317 + 3009

Sum of All = 3374

4 0

3 years ago