Which Interest Formula Do I Use?

Find the simple interest on $2,219 in principal, deposited for 6 years at a rate of 5.11%

• $I\ =\ prt$

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ pe^{rt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

Jasmine needs $30,000 to pay off a loan at the end of 5 years. How much must she deposit monthly into a savings account that yields 4% interest, compounded monthly?

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\left(\frac{r}{n}\right)}$

• $p\ =\ \frac{B}{\left(1+\frac{r}{n}\right)^{nt}}$

• $P\ =\ \frac{B\left(\frac{r}{n}\right)}{\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}$

Austin deposits $2,250 into a one year CD at an interest rate of 5.3%, compounded daily. What is his ending balance.

• $I\ =prt$

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ pe^{rt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\left(\frac{r}{n}\right)}$

Stephanie signed up for a direct deposit transfer into her savings account from her checking account. Every month $150 is withdrawn from her checking account. The interest in this account is at 2.6% compounded monthly. How much will be in the account at the end of 6.5 years?

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\left(\frac{r}{n}\right)}$

• $p\ =\ \frac{B}{\left(1+\frac{r}{n}\right)^{nt}}$

• $P\ =\ \frac{B\left(\frac{r}{n}\right)}{\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}$

Ryan deposited $3,000 into an account that pays 1.5% interest compounded continuously. What is his balance after 2 years?

• $I\ =\ prt$

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ pe^{rt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\left(\frac{r}{n}\right)}$

Terri wants to purchase a car in 2 years. She expects to need $2,500 for a down payment. How much should she put in her account that pays 2.2% interest compounded daily?

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ \frac{p\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

• $p\ =\ \frac{B}{\left(1+\frac{r}{n}\right)^{nt}}$

• $P\ =\ \frac{B\left(\frac{r}{n}\right)}{\left(1+\frac{r}{n}\right)^{nt}-1}$

Bill deposited $3,500 into an account that pays 1.85% interest compounded weekly. How much will he have in his account at the end of 3 years?

• 
  

  $I\ =\ prt$
  

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ pe^{rt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

Trevor is putting $15 every biweekly pay into his savings account.  This account pays 2.04% interest compounded biweekly.  How much will he have in his account in 5 years?

•  $I\ =\ prt$  

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ pe^{rt}$

• $B\ =\ \frac{P\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

Timmy wants to have $2,000 saved in 6 months in order to purchase an engagement ring.  How much will he need to put into his account that pays 2.36% interest compounded monthly?

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ \frac{p\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

• $p\ =\ \frac{B}{\left(1+\frac{r}{n}\right)^{nt}}$

• $P\ =\ \frac{B\left(\frac{r}{n}\right)}{\left(1+\frac{r}{n}\right)^{nt}-1}$

Doug is saving for a down payment on a house.  He decides to put $150 from each weekly paycheck into an account for this purpose.  How much will he have in the account in 4 years if the account pays 2.63% interest compounded quarterly?

• $B\ =\ p\left(1+\frac{r}{n}\right)^{nt}$

• $B\ =\ \frac{p\left(\left(1+\frac{r}{n}\right)^{nt}-1\right)}{\frac{r}{n}}$

• $p\ =\ \frac{B}{\left(1+\frac{r}{n}\right)^{nt}}$

• $P\ =\ \frac{B\left(\frac{r}{n}\right)}{\left(1+\frac{r}{n}\right)^{nt}-1}$