Answer:
- <u>59.0891 g (rounded to 4 decimal places)</u>
Explanation:
<em>Half-life time</em> of a radioactive substance is the time for half of the substance to decay.
Thus, the amount of the radioactive substance that remains after a number n of half-lives is given by:
Where:
- A is the amount that remains of the substance after n half-lives have elapses, and
- A₀ is the starting amount of the substance.
In this problem, you have that the half-live for your sample (polonium-210) is 138 days and the number of days elapsed is 330 days. Thus, the number of half-lives elapsed is: 
- 330 days / 138 days = 2.3913
Therefore, the amount of polonium-210 that will be left in 330 days is:
 
        
             
        
        
        
<span>Hello : let
 A(-3,7)    B(3,3)
the slope is :   (YB - YA)/(XB -XA)
(3-7)/(3+3)  = -2/3
an equation is : y=ax+b     a is a slope</span>
y = (-2/3)x +b
 
the line through point B (3,3) :
 3 = (-2/3)(3)+b<span>
<span>b =5 
the equation is : y =(-2/3)x+5</span></span>
 
        
             
        
        
        
I belive this is hard for a 5th grader but my answer is c)2