Answer:
9r
Step-by-step explanation:
1.5r - 3r + 10.5r
10.5r + 1.5r = 12r
12r - 3r = 9r
Final Answer = 9r
 
        
             
        
        
        
Answer:
1780
Step-by-step explanation:
product means multiply 
20x89=1780
 
        
             
        
        
        
Answer: 
Step-by-step explanation:
Since, The total number of student = 300
Out of which,
The number of students who are only in Maths  = 120
And, The number of students who are only in Science  = 50
While, the students who are not from any subject = 100
Hence, the number of student who are from both maths and science = Total student - Maths student (only) - science student (only) - None
= 300 - 120 - 50 - 100
= 30
That is, there are 30 students who are both from science and maths,
Thus, the probability of selecting one student who is both from maths and science = 30/300 = 1/10