Civil Engineering - Water Supply Engineering - Discussion

Discussion Forum : Water Supply Engineering - Section 7 (Q.No. 5)
5.
The population of a city in 2000 is 50,000. The average increase in population over last 8 decades is 7500 and average incremental increase during 8 decades is 750. The population of the city based on incremental method, in the year 2020 will be
55,000
60,500
66,500
72,500
76,500
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
16 comments Page 1 of 2.

Renis@Gajipara said:   5 years ago
The population of the city based on the incremental method, in the year 2020.

i = 7500 & r = 750.
Pn = P + (i+r)n.
= 50000 + (7500+750)*2.
Pn = 66500.

Where,
P = Present population in 2000.
i = avg. increase in population.
r = avg. incremental increase.
n = Number of decades.
(10)

Thasni Kalam said:   3 years ago
According to Incremental increase method;

P=p+nx+n(n+1)/2*y
P - popln after n decades from the present.
p - present population
x - avg increase of population of known decades
y - avg of incremental increase of the known decades.


Then substitute these values in eqn
Here we want to find the 2020th population calculating from 2000-2020 n=2 decades
P=50000+2*7500+2(2+1)/2*750 = 67250
So, the correct answer is 67250.
(9)

Mahesh sinh said:   6 years ago
Pn = P+n(Ia+Iinc),
Pn = 5000+2(7500+750).
= 66500.
(2)

Pooja said:   5 years ago
Pn = Po + nx + [(n(n+1))/2]*y.
n = no Of decades,
x = avg increase in population,
y = avg. incremental increase,
Po = initial population.
(2)

Noini said:   5 years ago
Avg increase is 7500 calculated for 8 decades.

Then the total increase in population from 1930 is 7500x8=60000. If increase itself is 60000, what is the actual population in 1920 initially then? How can the population in 2000 be very less=50000?

Please anyone explain.
(2)

Aakriti pandey said:   3 years ago
What rate of supply would you recommend, for a town with a population of 50,000?

Anyone answer me.
(2)

Prashanth said:   5 years ago
@Jajhjiik.

How it came 3? please explain sir.
(1)

Anirban Roy said:   5 years ago
Yes, you are right @Pooja. So,

Pn = 55000 + 2 * 7500+(2 * 3÷2) * 750 = 67250.
(1)

Smith said:   5 years ago
Thanks all for eplaining the answer.
(1)

Jajhjiik said:   1 decade ago
According to incremental increase method, yn = yo+nr+n(n+1)/2xk.

yo = Initial population n = No of decades k = net incremental increase.

r = avg increase in population.

So, y 2020 = 50000+7500x2+3x750 = 67250.

Answer given is wrong.


Post your comments here:

Your comments will be displayed after verification.