The frequency of revision times is given by the product of the frequency
density value and the class width.
Correct response:
- The number of students are <u>72 students</u>
<h3>Methods of calculation using a histogram</h3>
The estimate of the number of students who revised for less than 45
minutes is given by the area, <em>A,</em> under the histogram to the left of the 45
minute mark as follows;
Frequency, f = Frequency density × Class width
Number of students = ∑f
Therefore;
A = 5 × 2 + 10 × 2.2 + 20 × 1.6 + 10 × 0.8 = 72
- The number of students that revised for less than 45 minutes = <u>72 </u>students
Learn more about histograms here:
brainly.com/question/17139138
Answer:
The given system of equations has solutions below:
1) The solution is (2,3)
2) The solution is (
)
3) The solution is infinitely many solutions
4) No solution
Step-by-step explanation:
Given system of equation are


To solve equation by using elimination method
Multiply eqn (2) into 2

Now subtracting (1) and (3)


_________________
7x=14
x=

Substitute x=2 in equation (1)
-2+2y=4
2y=4+2

y=3
Therefore the solution is (2,3)
2) Given equation is

4y-4=x
Rewritting as below

To solve equation by using elimination method
multiply (2) into 2

Adding (1) and (3)
-2x+y=3
2x-8y=-8
________
-7y=-5

substitute
in (1)




Therefore the solution is (
)
3) Given equation is 

equation (1) can be written as
2(3x+y)=10

3x+y=5
Therefore equations (1) and (2) are same therefore it has infinitely many solutions
4) Given equation is 

multiply equation (1) into 2

To solve equation by using elimination method
subtracting (2) and (3)
-2x-4y=28
-2x-4y=12
_______

therefore it has no solution
This is the awnser too this one
The perimeter of the a and BC is 14 unitsBecause if you add all of the sides together you get 14 and I need points
There u just needed to search the formula