Half-life and time with logs Quiz

Name: ______________________   Date: __________   Score: ____ / 10

10 questions. Calculator allowed. Show your working. steplyclass.com/algebra-2/half-life-and-time-with-logs/quiz/

1. 1

   A substance has a half-life of 5 years. How much of 80 g is left after 20 years?

   Answer: ____________________

2. 2

   A substance has a half-life of 10 years. How much of 200 mg is left after 30 years?

   Answer: ____________________

3. 3

   A substance has a half-life of 5 years. How long until 80 g decays to 10 g?
   1. A) t = 1080
   2. B) t = 3
   3. C) t = 10
   4. D) t = 15

4. 4

   A substance has a half-life of 6 hours. How long until 40 mg decays to 5 mg?

   Answer: ____________________

5. 5

   A substance has a half-life of 5 years. How much of 80 g is left after 12 years?

   Answer: ____________________

6. 6

   $500 grows by 4% a year. How many years until it is $800?

   Answer: ____________________

7. 7

   How long until $1000 invested at 6% compounded monthly grows to $2000?
   1. A) t ≈ 2
   2. B) t ≈ 11.58
   3. C) t ≈ 1.005
   4. D) t ≈ 2000

8. 8

   $2000 grows by 3% a year. How many years until it is $2600?

   Answer: ____________________

9. 9

   $1500 is invested at 6% compounded continuously. How long until it triples?
   1. A) t ≈ 3
   2. B) t ≈ 4500
   3. C) t ≈ 18.31
   4. D) t ≈ 183.1

10. 10

    How long until $3000 invested at 5% compounded monthly grows to $4500?

    Answer: ____________________