Question

एका गावाची लोकसंख्या 4235 आहे. ती दर 10 वर्षांनी 10% ने वाढते तर त्या गावची लोकसंख्या 20 वर्षांपूर्वी किती होती?

Answer 1

Given:

The population of a village is 4235.

If it grows by 10% every 10 years

To find:

What was the population of that village 20 years ago?

Solution:

The present population of the village = 4235

The rate of increase in population = 10%

Since the population increases every 10 years and we have to find the population 20 years ago,

⇒ the population have increased twice in 20 years

⇒ we will take the value of n = no. of years = 2 years

Let's assume "P" represents the population of the village 20 years ago

We know the formula for the population P after n years increasing at a constant rate of R% as:

$\boxed{\bold{Population\:after\:n\:years = P [1 + \frac{R}{100} ]^n}}$

Now, on substituting the given values in the formula above, we get

$4235 = P [1 + \frac{10}{100} ]^2$

$\implies 4235 = P [ \frac{110}{100} ]^2$

$\implies P = 4235 [ \frac{100}{110} ]^2$

$\implies P = 4235 [ \frac{10}{11} ]^2$

$\implies P = 4235 \times [ \frac{100}{121} ]$

$\implies P = 35 \times 100$

$\implies \bold{P = 3500}$

Thus, the population of that village 20 years ago was → 3500.

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Answer 2

Answer:

एका वस्तुची किंमत २०% ने वाढली असता पुर्वीच्या खरेदीत आहे त्याच रकमेत किती टक्के कमी होईल?