Exponentials from Word Problems

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

Katy deposited $90 in a savings account earning 5% interest, compounded quarterly. Which of the following equations could represent the amount of money in her account yearly?

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A city doubles its size every 64 years. If the population is currently 225,000, what will the population be in 128 years?

• The population will be 225,000.

• The population will be 450,000.

• The population will be 900,000.

• The population will be 1,800,000.

You have 30,016 grams of radioactive kind of rubidium. How much will be left after 54 minutes if its half-life is 18 minutes?

• 15,008 grams.

• 7,504 grams

• 3,752 grams.

• 1,876 grams.

Write and exponential function for the following problem: Mrs. Madison starts the year off with 100 pencils. Each week, half of the pencils disappear. How many would be left after x weeks?

Solve this problem: When the apocalypse began, there were 5 zombies. Each day that number tripled. How many zombies would there be after a week (7 days)?

• 22

• 9,218

• 10,935

• 915

Solve the problem: Mrs. Madison has discovered she likes to crochet. She went out an bought 7 skeins of yarn to start her collection. That collection has doubled each month. How many skeins of yarn would she have after 6 months?

• 512 skeins

• 448 skeins

• 98 skeins

• 235,298 skeins

What would be the multiplier for this problem? Matt has the chicken pox. On day one, he counted that he had 10 spots. Each day that number quadruples. How many would he have after 3 days?

• 10

• 3

• 4

• 1/4

A population of 1200 bacteria is doubling each day for x days.

Rapunzel's hair grew 16% each week she was in the tower. If her hair was 20 inches long when she was placed in the tower, what is a model for the growth of Rapunzel's hair?