The range of the top plot, hours spent by 13-15 year olds, is found by subtracting the highest value, 34, and the lowest value, 21. 34-21=13.
The mean of the top plot is found by adding together all of the data points and dividing by 10 (the number of data points):

The range of the bottom plot, minutes spent online by 16-18 year olds, is found by subtracting the highest value, 36, and the lowest value, 12. 36-12=24.
The mean of the bottom plot is found by adding together all of the data points and dividing by 11 (the number of data points):
Answer:
all sides are 7 units
Step-by-step explanation:
Since the triangle is equilateral then all 3 sides are equal in length
equate any 2 sides and solve for d
KL = LM
d + 2 = 12 - d ( add d to both sides )
2d + 2 = 12 ( subtract 2 from both sides )
2d = 10 ( divide both sides by 2 )
d = 5
KL = d + 2 = 5 + 2 = 7
LM = 12 - d = 12 - 5 = 7
KM = 4d - 13 = (4 × 5) - 13 = 20 - 13 = 7
Let a = aircraft 1 seats
Let b = aircraft 2 seats
Let c = aircraft 3 seats
From the information given above, let's make basic equations.




We can begin to plug in values we know.




We now know that the second aircraft has 138 seats. Now we can plug in this value to find the value of the other seats. Let's start with the first aircraft.



We now know that the first aircraft has 189 seats. Let's now finally solve for the third aircraft.



Finally, we know that aircraft 3 has 84 seats. To check our work, let's make sure that each of these values add up to 411.



This is true, therefore the values are correct.
Aircraft 1: 189 seats
Aircraft 2: 138 seats
Aircraft 3: 84 seats