Hi, For problem #7 & #9, the answers are given on the Chegg, but why do you need to use the natural log to solve these problems? Is there another way to solve these two problems NOT using formulas, but only using a financial calculator? The answer for #7: 9.84 years to double and

19.68 years to quadruple. The answer for #9: 34 years.

Thank you in advance!

7. Calculating the Number of Periods [LO4] At 7.3 percent interest, how long does it take to double your money? To quadruple it? 8. Calculating Interest Rates [LO3] According to the Census Bureau, in January 2013, the average house price in the United States was $306,900. In January 2000, the average price was $200,300. What was the annual increase in selling price? Calculating the Number of Periods [LO4] You're trying to save to buy a new $225,000 Ferrari. You have $45,000 today that can be invested at your bank. The bank pays 4.8 percent annual interest on its accounts. How long will it be before you have enough to buy the car? 1 d ed pencion