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122: Half Life and Doubling Time

Last updated almost 5 years ago
24 questions

Bell:

1

A person invested $6,000 in an account growing at a rate allowing the money to double every 11 years. How much money would be in the account after 19 years, to the nearest dollar?

We are going to use y=ae^{rt}

If it doubles, what is y?

1

What equation will you need to solve to find r? (remember, it doubles every 11 years)

1

What is r? Find it by solving [2], round to three decimal places.

1

Now answer the question: How much money would be in the account after 19 years, to the nearest dollar? Use the unrounded r value!

Notes L7-8:

For half/double we wil use continuous growth/decay y=ae^{rt}
  1. You will find r -- while you can round r to three decimals as a note to self; you must use the entire number when solving.
  2. then answer the question.
1

In a lab experiment, 2200 bacteria are placed in a petri dish. The conditions are such that the number of bacteria is able to double every 6 hours. How many bacteria would there be after 13 hours, to the nearest whole number?

Write the equation you wil solve. Your only variable should be r.

1

What is r?

1

Write the equation you will use the solve the problem. Your only variable should be y.

1

What is the answer?

1

Element X is a radioactive isotope such that every 9 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 9300 grams, how much of the element would remain after 3 years, to the nearest whole number?

Write the equation you wil solve. Your only variable should be r.

1

What is r?

1

Write the equation you will use the solve the problem. Your only variable should be y.

1

What is the answer?

1

A new car is purchased for $47,000 and over time its value depreciates by one half every 4.5 years. What is the value of the car 23 years after it was purchased, to the nearest hundred dollars?

Write the equation you wil solve. Your only variable should be r.

1

What is r?

1

Write the equation you will use the solve the problem. Your only variable should be y.

1

What is the answer?

1

A person invested $8,900 in an account growing at a rate allowing the money to double every 7 years. How long, to the nearest tenth of a year would it take for the value of the account to reach $20,600?

Write the equation you wil solve. Your only variable should be r.

1

What is r?

1

Which are we solving for? This is the only varible that should be in [20].

1

Write the equation you will use the solve the problem. Your only variable should be [19].

1

What is the answer?

1

Element X is a radioactive isotope such that every 6 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 20 grams, how long would it be until the mass of the sample reached 6 grams, to the nearest tenth of a year?

Final answer?

0

Choose all that are true

1

Please finish DeltaMath.