Interest Rates
Ms. Pangburn deposited $2,700 for 3 years on 2.45% interest rate in her savings account. How much simple interest will she earn?
What is $198.45
$1,200 is invested at an annual rate of 3.2%. What is the final amount after 6.7 years?
What is approximately $1,486.94
A radioactive isotope has a half life of 2.37 years. How much of the sample did we start with if it took 8.2 years to reach 82 grams?
What is 902.3 grams
Write the formula for Simple Interest
What is A= P + I = P + Prt
You take out a 4-year car loan for $12,499 with an interest rate of 12% per year, compounded annually. How much money will you owe the bank?
What is $19,667.42
What would Kylie Jenner's final balance be if she puts in $325 in the bank for 48 months with an interest rate of 12%?
What is $481
In 2007, there were 26,637 people that reported having the Swine Flu in the US. The number of people that reported having the disease steadily decreased at a rate of 13%. How many people reported having the disease in 2017?
What is approximately 7,260 people
The doctor gave you 700 milligrams of a drug. It has a half life of 4.5 hours. How much of the drug is in your bloodstream after 2 days?
What is 0.43 milligrams (remember to convert to hours!)
Write the formula for Compound Interest
What is A = P(1 + r/n)nt
How much money should Mr. Clean save in an account paying 5% interest compounded month if he wants to have $6,000 in 6 months?
What is $5,852.16
Jose invested $5,000 in an account that receives 3.2% interest compounded continuously. How much money will he have after two and a half years?
What is $5,416.44
At 5pm, you counted the number of bacteria cells in a Petrie dish. The growth rate is 20% and at midnight you counted 26,300 bacteria cells. How much did you originally count?
What is 6,485.5 bacteria cells
Bargon-72 has a half life of 1.39 years. If you start with 45 grams, how long did it take to reach 12.7 grams?
What is 2.54 years
Write the formula for Continuous Interest
What is A = Pert
Savage wants to buy a watch in 2 months for $1,750. He found a savings account that will pay 4.7% interest compounded quarterly. How much should he put in the savings account in order to have enough money?
What is $1,664
How much money should you put into your savings account if you want to have $1,500 after 25 weeks with an interest rate of 4%?
What is $1,384.62
The value of a stock when purchased is $10 a share. The stock decreased at a rate of 3% daily. Find the number of days it took for the stock to be worth $7.40.
(hint: pert)
What is approximately 10 days
You are observing a mystery radioactive isotope. When you first observed the isotope, there were 2.5 grams. You determine its half life to be 0.35 hours. How long did it take to reach 1.7 grams?
What is 0.19 hours
Write the formula for exponential growth & decay
What is A = Pert (growth) and A = Pe-rt (decay)
What percentage of interest compounded monthly should you charge people if you currently have $125 and want to have $1,234 in 6 months?
What is 5.58%
P Diddy gives you $202. What continuous interest rate should he charge you such that he quadruples his money back in 2 years?
What is 69.31%
The population in the town of Huntersville is presently 38,300. The town grows at an annual rate of 1.2%. Find the number of years it takes for the population to grow to 42,500.
What is 8.67 years (approximately 9 years)
At 7am, there are 540 milligrams of a drug in your bloodstream and at 6pm, there are 75 milligrams. What is the drug's half life?
What is 3.86 hours
Write the formula for half-life
What is A = Ao*2-t/h
A sum of $5,000 is invested at an interest rate of 9% per year. Find the time required for the money to double if the interest is compounded semi-annually.
What is 7.87 years (approximately 8 years)