Advertisements
Advertisements
प्रश्न
The population of a suburb is 16000. Find the rate of increase in the population if the population after two years is 17640.
उत्तर
Here, P = Population of a suburb = 16000
A = Population after two years =17640
R = R %
N = 2 years
A = P `(1 + "R"/100)^"N"`
= 17640 = 16000 `(1 + "R"/100)^2`
= `17640/16000` = `(1 + "R"/100)^2`
= `441/400` = `(1 + "R"/100)^2`
Taking square roots from both
= `(1 + "R"/100) = _-^+(21/20)`
= `"R"/100` = `21/20`
= `"R"/100 = _-^+ 21/20 - 1`
= `"R" /100 (+ 21/20-1) or (-21/20-1)`
= `"R"/100(1/20) or (-41/20)`
= `"R" = (1/20 xx 100) or (-41/20 xx 100)`
= R = 5 or R = −205
Hence, the rate of increase in the population is 5 p.c.p.a.
संबंधित प्रश्न
Compute the amount and the compound interest in the following by using the formulae when:
Principal = Rs 2000, Rate = 4 paise per rupee per annum, Time = 3 years
The difference between the compound interest and simple interest on a certain sum at 15% per annum for 3 years is Rs 283.50. Find the sum.
The population of a town increases at the rate of 50 per thousand. Its population after 2 years will be 22050. Find its present population.
The population of a certain city was 72000 on the last day of the year 1998. During next year it increased by 7% but due to an epidemic it decreased by 10% in the following year. What was its population at the end of the year 2000?
The population of a town increases at the rate of 40 per thousand annually. If the present population be 175760, what was the population three years ago.
The population of a city increases each year by 4% of what it had been at the beginning of each year. If the population in 1999 had been 6760000, find the population of the city in (i) 2001 (ii) 1997.
Ashish started the business with an initial investment of Rs 500000. In the first year he incurred a loss of 4%. However during the second year he earned a profit of 5% which in third year rose to 10%. Calculate the net profit for the entire period of 3 years.
The cost price of a machine is 2,50,000. If the rate of depreciation is 10% per year, find the depreciation in price of the machine after two years.
The population of a city was 20,000 in the year 1997. It increased at the rate of 5% p.a. Find the population at the end of the year 2000.
The cost of a sewing machine is Rs 7,000. Its value depreciates at 8% p.a. Then the value of the machine after 2 years is Rs 5,924.80.
