Answer:
It would take two half-lives which would be 130days
The substance has a half-life of 30 minutes. There has been two cycles that have occurred.
idk the last one
Explanation:
 
        
             
        
        
        
If an atom contains 13 protons, then it has <u>13 electrons.</u>
 
        
             
        
        
        
They can fight the infection but not the disease
        
                    
             
        
        
        
The value of g at sea level is 9.81 ms^-2.
The boy's mass is constant wherever he is in the universe but his weight will depend on the strength gravity where he is.
By proportion its value on the mountain peak  is (360 /400) * 9.81
= 0.9 * 9.81 = 8.83  ms^-2  to nearest hundredth,  (answer).