Answer:
156
Step-by-step explanation:
13 x 12 = 156
 
        
             
        
        
        
Answer:
B
Step-by-step explanation:
 
        
             
        
        
        
Given:
The function is:

Where p(t) represents the number of milligrams of the substance and t represents the time.
To find:
The correct explanation for the number 0.25 and 500 in the given function.
Solution:
The general exponential function is:
 ...(i)
           ...(i)
Where, a is the initial value and b is the growth/decay factor. If  , then decay factor and if
, then decay factor and if  , then growth factor.
, then growth factor.
We have,
 ...(ii)
           ...(ii)
On comparing (i) and (ii), we get
 , it means initial there are 500 milligrams of the substance.
, it means initial there are 500 milligrams of the substance.
 , this value is less than 1, it means the substance is decreasing by a factor of 0.25.
, this value is less than 1, it means the substance is decreasing by a factor of 0.25.
Therefore, 0.25 means the substance is decreasing by a factor of 0.25 and 500 means the initial value of substance is 500 milligram.