Answer:
 
  
Step-by-step explanation:
we know that    
The compound interest formula for this problem is equal to  
 
  
where  
A is the Final Investment Value  
P is the Principal amount of money to be invested  
r is the rate of interest  in decimal
t is Number of Time Periods  in years
in this problem we have  
 
  
substitute in the formula above  
 
  
 
  
 
        
             
        
        
        
8x - amount of boys
7x- amount of girls 
8x + 7x = 195
 
15x= 195  ( divide by 15)
x= 13
8x = 8 x 13 = 104
7x = 7 x 13= 91 
there are 104 boys, and 91 girls.
        
             
        
        
        
% increase  = 100 - 85
                        ---------     *  100
                          85
                  =   17.65 
                  = 18 % to nearest per cent
        
                    
             
        
        
        
Answer: 1/7
Step-by-step explanation:
7x=1
x=1/7