1.Use the "rule of 72" to estimate the doubling time (in years) for the interest rate, and then calculate it exactly. (Round your answers to two decimal places.)

7.7% compounded weekly.

"rule of 72"	yr
	Exact answer yr 2.Find the effective rate of the compound interest rate or investment. (Round your answer to two decimal places.) 18% compounded monthly. [Note: This rate is a typical credit card interest rate, often stated as 1.5% per month.] %