Find the time required for a $1000 investment to (a) double at interest rate r, compounded continuously, and (b) triple at interest rate r, compounded continuously. Round your results to two decimal places.$r = 2.5%$

Tell whether each statement is sometimes, always, or never true. Pointillism is a technique in which tiny dots of complementary colors are combined to form a picture. Which postulate ensures that a line connecting two of these points also lies in the plane containing the points?

Bill Rich signed a 180-day note for $1,250. He repaid the loan when due with interest at an annual rate of 12 % using a banker's year.

Kelly Bullock borrowed$4,800 for 6 months and paid $264 interest. What rate of interest did she pay?

In $1975$, interest rates were $7.98 \%$ and the rate of inflation was $12.26 \%$ in the United States. What was the real interest rate in $1975$? How would the purchasing power of your savings have changed over the year?

In this exercise, use the add-on method of calculating interest to find the total interest and the monthly payment.

Find the compound amount and compound interest if $4000 is invested for six years and interest is compounded continuously at the given annual rate. 9%

Bill Rich signed a 180-day note for $1,250. He repaid the loan when due with interest at an annual rate of 12 % using a banker's year.

Tony Colito paid$19.50 in interest on a loan of $2,600 for 1 month. What rate of interest did he pay?

A loan of $\$ 10,000$ was repaid at the end of $6$ months. What amount (principal and interest) was repaid, if a $6.5 \%$ annual rate of interest was charged?

Find the time required for a $1000 investment to (a) double at interest rate r, compounded continuously, and (b) triple at interest rate r, compounded continuously. Round your results to two decimal places.$r = 6%$

To make CDs look more attractive than they really are, some banks advertise that their rates are higher than their competitors’ rates; however, the fine print says that the rate is a simple interest rate. If a person deposits $10,000 at 10% per year simple interest, what compound interest rate would yield the same amount of money in 3 years?

Suppose that $20,000 is invested at continuous rate r and grows to$81,104 in 28 years. Find the interest rate r.

A couple decides to accept an adjustable rate, 30-year mortgage, in which the interest rate is fixed for the first 5 years and then may be adjusted annually beginning with year 6. Suppose that this couple borrows $305,000 with the annual interest rate, compounded monthly, for the first 5 years set at 5.5%. Suppose that the interest rate is increased to 6.75% for the remaining term of the loan. Calculate the monthly payment during the first 5 years and after the first 5 years. Find the amount of interest that would be paid over the term of this loan

Find the number of years it would take for $1200 to earn simple interest of$324 at an annual interest rate of 6% per year.

True or False? If true, prove it. If false, find the true answer. If you invest $500, an annual rate of interest of 3% yields more money in the first year than a 2.5% continuous rate of interest.