20...just draw 20 coins or something
        
             
        
        
        
Answer:
b. interest rate per period
Step-by-step explanation:
We know that 
Annual interest rate is APR or (r)
Po is initial amount 
n is number of periods
t is time in years
A is the amount after t years
so, 
i is the interest rate per period
Hence , 
answer is 
i is the interest rate per period
 
        
             
        
        
        
Answer:
$40
Step-by-step explanation:
If he spent $40 and has none left that means he currently has $0.
If you subtract $40 - b = $0 
b = $40
 
        
             
        
        
        
Answer:

Step-by-step explanation:





