We can define a variable "z" as the net percent change in area and 
set up the following equation:

z = (x + y + xy/100)%
= (40 + 30 + (40 * 30)/100)%
= 82%

This equation shows that the net percent change in area is 82%.

The reduction in consumption can be calculated by
taking the proportion of the original consumption value divided by the sum of the original consumption value and a percentage value,
and then multiplying the result by 100%.
Using the example values provided, the reduction in consumption would be calculated as follows:
Reduction in consumption = [(25/(100 + 25)] X 100)%
= [(25/125)] X 100)%
= 20%
This means that the consumption has been reduced by 20%

If the smaller number is 100, the first number is 120,
and the percentage that the smaller number is less than the greater number can be calculated by taking 20% of the first number and dividing it by the first number,
and then multiplying the result by 100%.
This gives a result of approximately 16 2/3%."

To find the population size at the beginning of the first year, we can use the formula:
Population at the beginning of the first year = (Total population at the end of the second year) / (1 + (percentage increase)) * (1 - (percentage increase))
Plugging in the values from the given information, we get:
Population at the beginning of the first year = 9975 / (1 + (5/100)) * (1 - (5/100))
Simplifying this expression, we get:
Population at the beginning of the first year = 9975 * (20/21) * (20/19)
Which simplifies to:
Population at the beginning of the first year = 10000
So the population at the beginning of the first year was 10000.

The solution would be calculated as follows:

50% of (x-y) = 30% of (x+y)
(50/100)(x-y) = (30/100)(x+y)
5(x-y) = 3(x+y)
2x = 8y
x = 4y

Therefore, the required percentage is ((y/x) * 100)% = ((y/4y) * 100) = 25%.

This means that y is equal to 25% of x 

To find what percentage one number is of another, you can use the formula:

percentage = (number being compared / reference number) * 100

So in this case, the percentage that 80 is of 64 can be found by plugging those numbers into the formula:

percentage = (80 / 64) * 100
= 1.25 * 100
= 125

Therefore, 80 is 125% of 64.

To do this, 
you can set up an equation to represent the total number of inhabitants after the two transactions have occurred, 
and then solve for the initial number of inhabitants.

The solution would be calculated as follows:

Let the total number of original inhabitants be x.

Then the number of inhabitants after 10% have died is
 (90/100)x.

The number of inhabitants after 25% have left is 
 ((75/100) * (90/100)x).

This is equal to 4050, so we have the equation: 
((75/100) * (90/100)x) = 4050.

Solving for x, 
we get: 
x = ((4050 * 40) / 27) = 6000.

This means that there were originally 6000 inhabitants in the village.

We can define a variable "z" as the net percent change in surface area and
set up the following equation:

z = (x + y + xy/100)%
= (10 + 10 + (10 * 10)/100)%
= 21%

This equation shows that the net percent change in surface area is 21%

To solve this problem, you can set up an equation using the given information. 
Let X be the number of runs made by running between the wickets and 
Y be the total number of runs scored. 
Then:

X + 3 * 4 + 8 * 6 = Y
X + 12 + 48 = Y
X = Y - 60
X/Y = (Y - 60)/Y
X/Y = 1 - 60/Y

In this case, Y is 120, so X/Y is equal to 1 - 60/120 = 1/2 = 50%.

Therefore, the batsman made 50% of his total score by running between the wickets.