56 Answered Questions for the topic Exponential Decay

How many phones where shipped in 2015?

please help me with this question: 3. The number of smart phones shipped globally can be modeled by the function, y = 1.78e 1.32, where x is the number of years since 2010 and y is the number of... more


Finding exponential decay given half-life problem

The half-life of a certain radioactive substance is 10 years. Initially there are 100 grams of the substance. Let A(t) be the number of grams of the substance at time t years. Find each of the... more
Exponential Decay Chemistry


exponential decay

The​ half-life of a radioactive substance is 33.9 years.a. Find the exponential decay model for this substance.b. How much of the sample of 1000 grams will remain after 20 ​years?c. How long will... more
Exponential Decay Chemistry


A 15 gram substance that's has a k value of 0.1405. what's the half life

Exponential Decay Chemistry


Question involving exponential decay

The half-life of radium-223 is approximately 1143 years. Use the formula A(t)=A_0 a^t to determine a and write a general formula, in the form A(t)=A_0 a^t, that describes the amount of radium-223... more
Exponential Decay Math Exponential Functions


Exponential decrease

A medicine is given with a dosage of 30mg, during the first 4 hours 17.7 mg of the drug is broken down. A body generally does this exponentially.   What is the rate of decay? When writing it as a... more
Exponential Decay


Lilly purchased a pan drive worth $800 in the first mounth of the year. It’s value depreciates by 2% per year. What is the vaule after six months?

I’m confused on what am I asked to do I need help getting starte.
Exponential Decay


10kg isotope decays to 4kg after 15 years. How much isotope remains after 18 years? (You can leave in exact form)

Last question on an assignment, thanks for the help.


Algebra 1- Exponential Growth & Decay

How are exponential growth and decay present in the real world? Give at least 2 examples for exponential growth and 2 examples of exponential decay. My Answer: I have only been able to think of one... more

Decay constant of radioactive isotope

A radioactive isotope decays according to the formula A(t)=Aoe^kt, where t is time in years. The initial amount was 10g and 8g of the isotope remained after 5 years. a) Find the decay constant,... more
Exponential Decay Precalculus


Please help asap

Measuring the amount of carbon-14 enables an archaeologist to determine the age of artifacts and fossils. In 1962, skeletal and fossil remains of a woman were found. The fossil was estimated to be... more
Exponential Decay


What is general shape of an exponential decay function? (see below)

I know for growth it is a steeply rising curve and feel like it would be the same for decay just opposite?  So, is it still B. ?   A.  A falling curve that approaches, but never reaches, the... more
Exponential Decay Algebra 2


What percent of the phosphorus-32 decays each day?

The amount y (in grams) of the radioactive isotope phosphorus-32 remaining after t days is y=a(0.5)t/14, where a is the initial amount (in grams). Round the answer to the nearest hundredth of a... more
Exponential Decay Exponential Functions


Find an exponential rule that would model the amount of Tc-99m left in the person at any time t in days.

Tc-99m is used to detect tumors in the body. The half life of Tc-99m is only 6 hours. Suppose an initial dosage of 20 mCi was administered. Find the rule.
Exponential Decay


my garden and reduces my space, on average, by 5% each year. If the garden started out at 850 sq ft approximately how many sq ft will there be in 12 years

This is talking about approximate doubling time and half-time decrease  
Exponential Decay


word problem

A certain species of animal is endangered and its numbers are decreasing 11% annually. There are currently 440 animals in the population. Which is an exponential function representing the... more



I need to find a formula for f-1(t) do I set the funtion =0 =x or what?
Exponential Decay Exponential Growth


Suppose that you have $6940 to invest. Which investment yields the greater return over 4 years: 9.45% compounded quarterly or 9.5% compounded semiannually?

The accumulated value of the 9.45% investment is .The accumulated value of the 9.5% investment is .The investment at ______% compounded _______ yield a greater return.
Exponential Decay Exponential Growth


Find the accumulated value of an investment of $12870 for 7 years at an annual interest rate of 7.4% if the money is

compounded seminannually: compounded monthly: compounded quarterly: compounded continuously:


A pie cools in a 70 degree room. The pie is 300 degrees. After ten minuites the pie cools to 260 degrees

Create a formula then find the temp of the pie after 120 minuites 


Exponential rate of growth/decay?

A study is done on the population of a certain fish species in a lake. Suppose that the population size P(t) after t years is given by the following exponential function. P(t)= 280(0.81)^t. What... more
Exponential Decay Exponential Growth


Rewrite y=(1.4)^t+8 in the form y=a(1+r)^t

I keep getting the wrong answer.. not sure if it goes to 4%? idk 

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