The population of Paris is 2,31,525 and it has been growing annually at a rate of 5%. What was the
population 3 years ago?
0 2,12,500
0 2,10,000
0 1.95,000
0 2,00,000
Answers
Answer:
The Formula for Population Growth
Formula 1: Let P be the population of a city at the beginning of the certain year and the population grows at a constant rate R% per annum, then:
P
o
p
u
l
a
t
i
o
n
a
f
t
e
r
n
y
e
a
r
s
=
P
(
1
+
R
100
)
n
Formula 2: Let P be the population of a city or a town at the beginning of a certain year. If the population grows at the rate of R1% during the first year and R2% during the second year, then:
P
o
p
u
l
a
t
i
o
n
a
f
t
e
r
2
y
e
a
r
s
=
P
(
1
+
R
1
100
)
×
(
1
+
R
2
100
)
Formula 3: Let P be the population a city or a town at the beginning of a certain year. If the population decrease at the rate of R% per annum, then:
P
o
p
u
l
a
t
i
o
n
a
f
t
e
r
n
y
e
a
r
s
=
P
(
1
−
R
100
)
n
growth
Learn Uses of Percentages here.
Depreciation
It is a well-known fact that the constant use of any machine or any other article causes wear and tear due to which its value decreases with time. The relative decreases in the value of a machine over a period of time is its depreciation. Depreciation per unit of time gives the rate of depreciation. The value at any time is called the depreciated value.
Quick summary
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Calculation of Growth and Depreciation Using Compound Interest Formula
2 mins read
Formula for Depreciation
First Formula: If V0 is the value of an article at a certain time and R% per annum is the rate of depreciation, then the value of Vn at the end of a year is:
V
n
=
V
0
(
1
−
R
100
)
n
Second Formula: If V0 is the value of an article at a certain time and the rate of depreciation is R1% for the first n1 years, R2% for next n2 years and so on and Rk% for the last nk years the value at the end of n1 + n2 +………..+ nk years is:
V
=
V
0
(
1
+
R
1
100
)
n
1
×
(
1
+
R
2
100
)
n
2
…
…
×
(
1
+
R
2
100
)
n
k