7*7=49+5=54 just use PEMDAS
        
                    
             
        
        
        
3/4+-2 1/9=your ****ing answer
        
             
        
        
        
To solve this we are going to use the half life equation 

Where:

 is the initial sample

 is the time in years

 is the half life of the substance

 is the remainder quantity after 

 years 
From the problem we know that:



Lets replace those values in our equation to find 

:




We can conclude that after 1600 years of radioactive decay, the mass of the 100-gram sample will be 
91.7 grams.
 
        
        
        
94.2 in would be your answer
        
             
        
        
        
Answer:
2/15
Step-by-step explanation:
1/3-1/5
5/15-3/15
= 2/15