Advertisements
Advertisements
प्रश्न
The population of a town was decreasing every year due to migration, poverty and unemployment. The present population of the town is 6,31,680. Last year the migration was 4% and the year before last, it was 6%. What was the population two years ago?
Advertisements
उत्तर
Let the population two years ago = P (Principal)
Present population of the town = A = 631680
Rate of migration in 1st year = 4%
Rate of migration in 2nd year = 6%
By using the formula,
`A = P(1 - R/100)(1 - R/100)`
⇒ `631680 = P(1 - 4/100)(1 - 6/100)`
⇒ `631680 = P xx 24/25 xx 47/50`
⇒ `P = (631680 xx 25 xx 50)/(24 xx 47)`
⇒ P = 560 × 1250 = 700000
Hence, the population of town was 700000 two years ago.
APPEARS IN
संबंधित प्रश्न
Compute the amount and the compound interest in the following by using the formulae when:
Principal = Rs 3000, Rate = 18%, Time = 2 years
The compound interest on Rs 1800 at 10% per annum for a certain period of time is Rs 378. Find the time in years.
Three years ago, the population of a town was 50000. If the annual increase during three successive years be at the rate of 4%, 5% and 3% respectively, find the present population.
In a factory the production of scooters rose to 46305 from 40000 in 3 years. Find the annual rate of growth of the production of scooters.
The count of bacteria in a culture grows by 10% in the first hour, decreases by 8% in the second hour and again increases by 12% in the third hour. If the count of bacteria in the sample is 13125000, what will be the count of bacteria after 3 hours?
6400 workers were employed to construct a river bridge in four years. At the end of the first year, 25% workers were retrenched. At the end of the second year, 25% of those working at that time were retrenched. However, to complete the project in time, the number of workers was increased by 25% at the end of the third year. How many workers were working during the fourth year?
In a forest there are 40,000 trees. Find the expected number of trees after 3 years if the objective is to increase the number at the rate 5% per year.
Find the compound interest if the amount of a certain principal after two years is ₹ 4036.80 at the rate of 16 p.c.p.a.
Find the amount and the compound interest on ₹ 4,000 in 2 years, if the rate of interest for the first year is 10% and for the second year is 15%.
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.
