Question 68

At present, the number of trees in a village is 52,020. It increases annually at the rate of 2%. What was the number of trees in the village two years ago?

Solution

Let's assume the number of trees in the village two years ago is 'y'.

At present, the number of trees in a village is 52,020. It increases annually at the rate of 2%.

y of (100+2)% of (100+2)% = 52020

y of 102% of 102% = 52020

$$y\times\frac{102}{100}\times\frac{102}{100}=52020$$

$$y\times1.02\times1.02=52020$$
1.0404y = 52020

number of trees in the village two years ago = y = 50000

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