Answer:
the first one from the top
 
        
             
        
        
        
Answer:
Step-by-step explanation:
Robert Boyle was one of the most prolific figures in the scientific revolution and the leading scientist of his day. He discovered the Boyle's law, which shows that the volume and pressure of a gas are proportionally related.
 
        
             
        
        
        
20 is the answer.
15% of 50= 7.5
45% of 50= 22.5
22.5+7.5=30
50-30=20.
        
             
        
        
        
Answer:
112
Step-by-step explanation:
Define the variables:
x = number of French students sent by the school
Write the equation:
x / 21 = 1 / 3
Solve:
x = 7
The school sent 7 French students and 21 German students, for a total of 28 students.
The other 3 schools also sent 28 students.  So the total number of students sent is:
4 × 28 = 112
 
        
                    
             
        
        
        
Answer:
1 1/2
Step-by-step explanation:
Turn 8 1/4 into 33/4 
Then multiply 33/4*2/11 to get 66/44 then simplify to 1 1/2