Answer:
a) 19 students
b) the mean 3 9/19
the median 3
the mode 3
c) the range 6
Step-by-step explanation:
The data set shows that 
0 points gets 1 student,
1 point gets 1 student,
2 points get 2 students,
3 points get 6 students,
4 points get 4 students,
5 points get 3 students and
6 points get 2 students.
a) There are 1+1+2+6+4+3+2=19 students.
b) The mean is 

The average score is 3 9/19 points.
The median is 10th term in the data set - 3 points (means the middle score in the data set)
The mode is 3 points (means most happened score)
c) The range of the data is 6-0=6 points.
 
        
             
        
        
        
Area of triangle = base x height x 1/2
Area of the triangle:
= 12 x 15 x 1/2
= 180 x 1/2 
= 90 units^2
        
                    
             
        
        
        
Answer:
2 1/10 miles.
Step-by-step explanation:
8 - (2 1/2 + 3 2/5)
= 8 -  (5/2  + 17/5)
= 8 - (25/10 + 34/10)
= 8 - 59/10
= 80/10 - 59/10
= 21/10
= 2 1/10 miles.