Solving Word Problems with Logs:

1. A piece of fossilized wood was analyzed and it was found the original amount was 85g. The half life of C-14 is 5760 years. (a) If the amount of C-14 left now is 50g , calculate the age of the wood. (b) How much will be left in 8000 years? (c) When there will be 25 g left?

2. During an experiment it was recorded that there are 25 bacteria present originally in a culture. After 1 hour there are 2465 present. What is the doubling period?

3. In 1976 a research hospital bought half a gram of radium for cancer research. Assuming the hospital still exists, how much of this radium will the hospital have in the year 6836 if the half life of radium is 1620?

nt  r  4. The formula A  P1  is used to determine compound interest.  n  A is the future value of the investment P is the principal or the amount originally invested R is the interest rate n is the number of times the money is compounded in one year t is the time in years

(a) Determine how long it takes (to the nearest month) for the principal sum of $1000 to produce an amount of $2000 if the annual interest rate is 6% with the interest compounded monthly.

(b) Determine how much money you would have after 10 years if you deposited $500 into this account.

Solving Word Problems with Logs:

1. A piece of fossilized wood was analyzed and it was found the original amount was 85g. The half life of C-14 is 5760 years. (a) If the amount of C-14 left now is 50g , calculate the age of the wood. (b) How much will be left in 8000 years? (c) When there will be 25 g left?

2. During an experiment it was recorded that there are 25 bacteria present originally in a culture. After 1 hour there are 2465 present. What is the doubling period?

3. In 1976 a research hospital bought half a gram of radium for cancer research. Assuming the hospital still exists, how much of this radium will the hospital have in the year 6836 if the half life of radium is 1620?

nt  r  4. The formula A  P1  is used to determine compound interest.  n  A is the future value of the investment P is the principal or the amount originally invested R is the interest rate n is the number of times the money is compounded in one year t is the time in years

(a) Determine how long it takes (to the nearest month) for the principal sum of $1000 to produce an amount of $2000 if the annual interest rate is 6% with the interest compounded monthly.

(b) Determine how much money you would have after 10 years if you deposited $500 into this account.