The amount of the substance (At) at any time t is calculated through the equation,
At = (A0)(e^-kt)
where A0 is the initial amount and k is constant.
For the half-life,
ln (At / A0) = ln 0.5 = -k(5270 years)
The value of k is 1.3153x10^-4 / year.
Substituting this value to the same equation, where At = 0.25A0
ln 0.25 = -(1.3153 x 10^-4)(t)
The value of t from this equation is 10540 years. The closest value to this is letter A.
We are given with a circle and we need to find the <em>equation of the circle</em> , but first let's recall that , the equation of a circle with radius<em> 'r'</em> and centre at <em>(h,k) </em>is given by
Now , here as as the circle cuts the +ve x-axis at (9,0) . So , it's radius is 9 units or the 2nd way is to measure the distance from centre of the circle to the point where the circle cuts the graph , as the centre is at Origin , so here <em>(h,k) = (0,0)</em> .Which means that the centre is located at the point whose coordinates are<em> (0,0)</em> which is also known as origin . Now , finding the equation of the circle :-


<em>This is the required equation of Circle</em>
Answer:
Junita
Step-by-step explanation:

junita scored a 83.3%
A) 2.85g+3.15c
B)2.85(8.4)+3.15(6)=$42.84
Answer:
22
Step-by-step explanation:
Missy has 156 cards in total. Since we know she has 4 times as many as them, we divide 156 by 4
156/4= 39
Ashe has 17 cards and we still don't know how many Caleb has. Since we know that they have 39 cards together, we need to subtract Ashe's cards to find how many Caleb has
39-17=22
Let's check our work
Caleb has 22 cards
Ashe has 17 cards
Together they have 39
Which is 4 times less than how many cards Missy has
Missy has 156 cards
We are correct!