Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
The population of a place increased to 54,000 in 2003 at a rate of 5% per annum. what would be its population in 2005?
In a laboratory, the count of bacteria in a certain experiment was increasing at the rate of 2.5% per hour. Find the bacteria at the end of 2 hours if the count was initially 5,06,000.
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 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 production of a mixi company in 1996 was 8000 mixies. Due to increase in demand it increases its production by 15% in the next two years and after two years its demand decreases by 5%. What will be its production after 3 years?
To start a business, Shalaka has taken a loan of ₹8000 at a rate of 10 `1/2` p.c.p.a. After two years, how much compound interest will she have to pay?
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.
A principal amounts to ₹ 13,924 in 2 years by compound interest at 18 p.c.p.a. Find the principal.
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.
