5. The population of a certain country is known to increase at a rate proportional fo the number of people presently living in the country. If after two years the population has doubled, and after three years the population is 20,000, find the number of people initially living in the country. 6. In a certain culture of bacteria, the rate of increase is proportional to the number present. (a) If it is found that the number doubles in 6 hrs, how many may be expected at the end of 18 hrs? (b) If there are 102 at the end of 4 hrs, and 8 x 102 at the end of 8 hrs, how many were there in the beginning? Brino

5. The population of a certain country is known to increase at a rate proportional fo the number of people presently living in the country. If after two years the population has doubled, and after three years the population is 20,000, find the number of people initially living in the country. 6. In a certain culture of bacteria, the rate of increase is proportional to the number present. (a) If it is found that the number doubles in 6 hrs, how many may be expected at the end of 18 hrs? (b) If there are 102 at the end of 4 hrs, and 8 x 102 at the end of 8 hrs, how many were there in the beginning? Brino

Sustainable Energy

2nd Edition

ISBN:9781337551663

Author:DUNLAP, Richard A.

Publisher:DUNLAP, Richard A.

Chapter17: Energy Conservation

Section: Chapter Questions

Problem 1P

See similar textbooks

Related questions

Q: You are designing a reactor that uses chlorine in a plug flow reactor or a completely stirred tank…

A: Given Min contact time = 30 min Water treated at a rate of 1000 gal/min

Q: A waste water is to be disinfected with chlorine to kill 90% of microorganisms. The number of…

A: As Per question,

Q: The growth rate of a bacteria culture is proportional to the number of bacteria present. If a…

A: From the given data : Initial population of bacteria = 100 Bacteria culture is proportional to the…

Q: Suppose that a quantity of a radioactive substance originally weighing Xo grams decomposes at a rate…

Q: A bacterial population is known to have a logistic growth pattern with initial population 1000 and…

A: Given:- A bacterial population is known to have a logistic growth pattern with initial population…

Q: One hour after a bacteria colony starts growing, a scientist determines that there are 9000 bacteria…

A: This problem is related to population forecasting from Environment Engineering. Calculate the…

Q: how long will it take to achieve the same 99% killing rate for the virus? (assuming other conditions…

Q: A group of students took sample of the influent ( Raw sewage ) and effluent ( treated sewage ) of…

A: Raw sewage contains more organic matter i.e concentration of organic matter is more in raw sewage as…

Q: you collect a 1-liter sample of water from a river and perform a BOd test in the lab. at the…

Q: Initially 100 milligrams of a radioactive substance were present. After 6 hours the mass had…

A: Using decay formula:Xt=Xoe-ktso,Xo=100mglXt=100-3% of 100=97mglso,97=100e-k6k=ln0.97-6k=0.00507hr-1

Q: initial population of a microbe species cultivated in the petri dish is 1200. After 6 hours, the…

A: Assuming Exponentially growing rate

Q: The rate of growth of a bacterial colony is related to the square of the number of bacteria present…

A: The values given in the question are as follows Initially quantity of bacteria(qo)=100 The rate of…

Q: Group of Scientist performed an experiment to determine the effectiveness of a chemical to…

A: Given data, Initial number of bacteria P = 40 Initial time = 2 hours Bacteria after 2 hours = 200

Q: A population of the of bacteria grows at the rate proportional to the number of bacteria at the…

Q: Suppose that at the start of an experiment there are 8,000 bactena A growth inhibitor and a lethal…

Q: a pond is used to treat a dilute municipal wastewater before the liquid is discharged into a river.…

A: The objective of the question is to determine the BOD concentration at the outflow of the pond and…

Q: Question An effluent at a flow rate of 2670 m³/d from a sewage treatment plant is to be disinfected.…

A: Given data- Flow rate- Q=2670 m3/d,chlorine dose=15 mg/L,Nt=Noe-0.145t, Nt=number of micro-organisms…

Q: A colony of bacteria grows at a rate proportional to the size of the its population P at time t (in…

A: Initial population, Po of bacteria = 39959 Also, there is sufficient food, no predators, and no…

Q: Families in a community in a developing country use large, 200.0 L drums to un-treated surface…

A: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question and…

Q: Consider a tank used in certain hydrodynamic experiments. After one experiment the tank contains…

Q: Differential equation. Solve the application problem. Show complete details of your solution. The…

Q: A bacterial population Z is known to have a rate of growth proportional to Z itself. If between noon…

Q: 3. A chemical reaction of a certain substance decays at a rate proportional to the undecayed amount.…

A: Given data of a Chemical substance :- Initial amount (No) = 500 After 2 days Substance lost = 150…

Q: Advection, diffusion, and reaction in a channel Approximately 50 m3 of an agricultural pesticide…

Q: Chlorine is used for primary disinfection at a water treatment plant that treats 0.20 m^3/s of…

Concept explainers

Landfills

The landfill is a site used for the disposal of waste materials. The landfill is a solid waste facility that is often known as a dumping ground. The image below shows a landfill site in Hawaii. Landfilling is the most ancient and common method used for the disposal of waste. For the landfill, a deep trench is constructed in an isolated place away from the city. The trench for landfills is designed properly after analyzing the total population and the waste generation per capita. The waste is dumped into the trench and after every layer of waste, a layer of soil is spread on the top of it.

Question

5. The population of a certain country is known to increase at a rate proportional to the
number of people presently living in the country. If after two years the population has
doubled, and after three years the population is 20,000, find the number of people
initially living in the country.
6. In a certain culture of bacteria, the rate of increase is proportional to the number
present. (a) If it is found that the number doubles in 6 hrs, how many may be expected
at the end of 18 hrs? (b) If there are 102 at the end of 4 hrs, and 8 x 102 at the end of
8 hrs, how many were there in the beginning?
calt Prino

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Step by step

Solved in 2 steps with 2 images

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.

Similar questions

A waste water is to be disinfected with chlorine to kill 90% of microorganisms. The number of micro-organisms surviving at time 't is modelled by N₁ = No 1+kt' where N is number of microorganisms at t = 0, and k is rate of kill in min-1. It was observed that after 10 minutes, 50% of micro-organisms were killed, and after 15 minutes from start, temperature is raised such that kill rate becomes double. The time taken in killing of micro-organisms from 0.5 No to 0.9 No is
A population of the of bacteria grows at the rate proportional to the number of bacteria at the time. There were initially 200 bacteria, and after 12 hours the population muliplied by 10. How many bacteria would there be after 24 hours.
find the differential equation of the following numbers (1, 2 and 3)
Question An effluent at a flow rate of 2670 m³/d from a sewage treatment plant is to be disinfected. The laboratory data of disinfection studies with a chlorine dosage of 15 mg/l yield the model N₁-Noe 0.145t where N₁= number of micro-organisms surviving at time t (in min.) and No= number of micro- organism present initially (at t=0). The volume of disinfection unit (in m³) required to achieve a 98% kill of micro-organisms is_
Suppose that at the start of an experiment there are 8,000 bactena A growth inhibitor and a lethal pathogen are introduced into the colony. After two hours 1,000 bactena are dead. If the death rates are exponential, 21 How long will it take for the population to drop below 5,000? 2.2 How long will it take for two-thirds of the bacteria to die? Round your answers to the nearest tenth N = Noekt
3. A chemical reaction of a certain substance decays at a rate proportional to the undecayed amount. Initially, there are 500g of the substance and after 2days, it is found out that the substance lost 150g. Determine the amount of converted substance after 10days.
4
One hour after a bacteria colony starts growing, a scientist determines that there are 9000 bacteria present. After another hour, there are 12,000 bacteria. How many bacteria were present initially? A) 3850 B) 6750 C) 9000 D) 16000
you collect a 1-liter sample of water from a river and perform a BOd test in the lab. at the beginning of the experiment, your water contains 8.7 mg/l of dissolved oxygen, and after 5 days you have only 5.0 mg/l of dissolved oxygen? a) what is the biological oxygen demand of the water - that is the amount of oxygen consumed during the 5 day period? b) Assuming all of the organic material in the water has the chemical formula CH2O, what mass of this material must have been present originally to consume that much oxygen?
Simple chemical conversion The population of a certain country has grown at a rate proportional to the number of people in the country.At present ,the country has 80 millions inhabitants.Ten years ago it had 70 million assuming that this trend continues.Find a. An expression for the approximate number of people living in the country at any time(taking t=0 to be the present time) b. The approximate number of people who will inhabit the country at the end of the next ten-year period.
The first-order reaction rate coefficient may carry different units such as hour-1 or day-1. In some application, you may need to convert units for your calculation. A value of k = 1.0 day-1 is equivalent to what hour
Q2.3 The half-life of a pesticide is 7 days. Determine the rate constant and calculate the time it will take to remove 98% of pesticide present in water.