The number of smokers is decreasing at the rate of 6 \frac{1}{4} % per year due to publicity of anti-smoking. If at present the number of smokers in a town is 22500, find the number of smokers of that town 2 years ago.
WBBSE
Class X
Mathematics
Compound Interest
05 Mark
2023
Amount (A) = ₹ 22500
Principal = P
Rate (r) = 61\over 4 %
time (n) = 2
A = P (1 – \text{r}\over 100)n
or, 22500 = P(1 – 25\over 4 × 100)2
or, 22500 = P(15\over 16)2
or, 22500 = P15\over 16 × 15\over 16
or, P = 22500 × 16\over 15 × 16\over 15
or, p = 25600
Thus, 2 years ago there were 25600 smokers.
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