Exponential Word Problems with Compound Growth and Half-Like

During a certain period of time, about 70 northern sea otters had an annual growth of 18%. Use an exponential function to find the number of sea otters after 4 years.
Round to the nearest whole number.

A population of fish starts at 8,000 and decreases by 6% per year. Use an exponential function to find the population of fish in 10 years.

Round to the nearest whole number.

Twenty years ago, Mr. Davis purchased his home for $160,000. Since then, the value of the home has increased about 5% per year. Use an exponential function to find the value of the home today.

Round to two decimal places (like money).

North Dakota has recently had the fastest growing population out of all 50 states. On Jan 1, 2013, the population of North Dakota was 700,000 people. North Dakota’s population has been growing by 5% per year. Express North Dakota’s population, N, in terms of years since 2013, t. Check the BEST answer:

• N=700,000(1.05)t

• N=700,000(1.5)t

• N=700,000(1-0.05)^t

• N=700,000(0.95)^t

An air freshener starts with 30 grams of fluid, and the amount of fluid decreases by 12% per day. Express the amount of grams of freshener, Q, that remains, t, days after it has begun being used. Check the BEST answer: (HINT: that means simplify what is in the parenthesis)

• Q=30(1+0.12)^t

• Q=30(1-0.12)^t

• Q=30(0.88)^t

• Q=12(1.30)^t

What is the initial quantity?

You start an account with $500 and an interest rate of 6% compounded yearly. How much is in the account after 3 years?

Round to the nearest cent. (two decimal places)

Find the balance in an account that has $300 invested at 6.5% for 4 years compounded semi-annually.

• $387.47

• $496.50

• $7,800.00

• $385.94

Derrick has $1,000 in a savings account that ears 15% interest, compounded monthly. To the nearest cent, how much will he have in 2 years?

• $5,350.25

• $1,322.50

• $1,025.16

• $1,347.35

Ash has $8,000 in a savings account. The interest rate is 3% compounded once a year.

To the nearest cent, how much will he have in his account in 4 years?

• $9,004.07

• $2,2848.80

• $9,011.94

• $8,242.71