The complete table will be:

<u><em>Explanation</em></u>
Suppose, the number of sit-ups in Sunday is 
Mean is the simple average of some numbers. <u>For finding the mean number</u> of sit-ups per day, we need to <u>divide the 'total number of sit-ups' by the 'total number of days'</u>.
Here the total number of days is 7 and the total number of sit-ups for 7 days 
Given that, the mean number of sit-ups per day is 100. So, the equation will be...

So, the number of sit-ups you have to do Sunday is 175.
Answer:
Yes
Step-by-step explanation:
Answer:
Length = 27 metres
Width = 9 metres
Step-by-step explanation:
Consider the width to be x.
Then the length will be 3x.
The perimeter is 66m when the width is increased by 1m and the length is decreased by 4m.
So the dimensions will become:
Length=3x-4
Width=x+1
Now solve for the variable x using the formula for perimeter of a rectangle:
P = 2(l+b)
66 = 2(3x-4+x+1) (Divide both sides by 2 and simplify the parentheses)
33 = 4x-3 (Add 3 to both sides)
36 = 4x (Divide both sides by 4)
x = 9
Now plug-in the value of x into the original dimensions which were:
Length=3x
Width=x
So the dimensions are:
Length = 27 metres
Width = 9 metres