Answer

Verified

408.3k+ views

Hint: In this question assume any variable be the population of village 2 years ago, then apply the concept that if p% population is decreased from present population say (q), then the present population becomes $\left( {q - \dfrac{p}{{100}}q} \right)$ so, use this concept to reach the solution of the question.

Let the population of the village 2 years ago be x.

Now it is given that the first year it was decreased by 6% due to migration, poverty and unemployment.

So, we have to subtract 6% of x from x, to get the population this year, let the population this year be y.

$ \Rightarrow y = x - \dfrac{6}{{100}}x$…………… (1)

Now next year the population of the village which is y now and it is decreased by 4% due to migration, poverty and unemployment, so we have to subtract 4% of y from y, let the population this year be z.

$ \Rightarrow z = y - \dfrac{4}{{100}}y$…………… (2)

Now it is also given that the population this year was $315,840$.

$ \Rightarrow z = 315,840$

Now from equation (2) we have,

$315,840 = y - \dfrac{4}{{100}}y$

$

\Rightarrow 315,840 = y - \dfrac{4}{{100}}y \\

\Rightarrow 315,840 = y - \dfrac{1}{{25}}y \\

\Rightarrow 315,840 = \dfrac{{24}}{{25}}y \\

\Rightarrow y = \dfrac{{315,840 \times 25}}{{24}} = 13,160 \times 25 = 329,000 \\

$

Now from equation (1) we have

$

329,000 = x - \dfrac{6}{{100}}x \\

\Rightarrow 329,000 = x - \dfrac{3}{{50}}x \\

\Rightarrow 329,000 = \dfrac{{47}}{{50}}x \\

\Rightarrow x = \dfrac{{329,000 \times 50}}{{47}} = 7000 \times 50 = 350,000 \\

$

So, the required population of the village 2 years ago is 350,000.

Note: In such types of questions remember that the data given in question is that the present population of the village is $315,840$ and Last year the migration was 4% and the year before last, it was 6% , so let the population of the village 2 years ago be x and this year the population is decreased by 6% and next year the population is decreased by 4% now construct the equations as above according to given information and simplify, we will get the required population 2 years ago.

Let the population of the village 2 years ago be x.

Now it is given that the first year it was decreased by 6% due to migration, poverty and unemployment.

So, we have to subtract 6% of x from x, to get the population this year, let the population this year be y.

$ \Rightarrow y = x - \dfrac{6}{{100}}x$…………… (1)

Now next year the population of the village which is y now and it is decreased by 4% due to migration, poverty and unemployment, so we have to subtract 4% of y from y, let the population this year be z.

$ \Rightarrow z = y - \dfrac{4}{{100}}y$…………… (2)

Now it is also given that the population this year was $315,840$.

$ \Rightarrow z = 315,840$

Now from equation (2) we have,

$315,840 = y - \dfrac{4}{{100}}y$

$

\Rightarrow 315,840 = y - \dfrac{4}{{100}}y \\

\Rightarrow 315,840 = y - \dfrac{1}{{25}}y \\

\Rightarrow 315,840 = \dfrac{{24}}{{25}}y \\

\Rightarrow y = \dfrac{{315,840 \times 25}}{{24}} = 13,160 \times 25 = 329,000 \\

$

Now from equation (1) we have

$

329,000 = x - \dfrac{6}{{100}}x \\

\Rightarrow 329,000 = x - \dfrac{3}{{50}}x \\

\Rightarrow 329,000 = \dfrac{{47}}{{50}}x \\

\Rightarrow x = \dfrac{{329,000 \times 50}}{{47}} = 7000 \times 50 = 350,000 \\

$

So, the required population of the village 2 years ago is 350,000.

Note: In such types of questions remember that the data given in question is that the present population of the village is $315,840$ and Last year the migration was 4% and the year before last, it was 6% , so let the population of the village 2 years ago be x and this year the population is decreased by 6% and next year the population is decreased by 4% now construct the equations as above according to given information and simplify, we will get the required population 2 years ago.

Recently Updated Pages

The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths

Define absolute refractive index of a medium

Find out what do the algal bloom and redtides sign class 10 biology CBSE

Prove that the function fleft x right xn is continuous class 12 maths CBSE

Find the values of other five trigonometric functions class 10 maths CBSE

Find the values of other five trigonometric ratios class 10 maths CBSE

Trending doubts

How do you solve x2 11x + 28 0 using the quadratic class 10 maths CBSE

Fill the blanks with the suitable prepositions 1 The class 9 english CBSE

Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE

Explain why a There is no atmosphere on the moon b class 11 physics CBSE

Difference Between Plant Cell and Animal Cell

Can anyone list 10 advantages and disadvantages of friction

State and prove Bernoullis theorem class 11 physics CBSE

The ice floats on water because A solid have lesser class 9 chemistry CBSE

State Newtons formula for the velocity of sound in class 11 physics CBSE