Consider this example provided by my teacher:

3. To solve the following problem, refer to the formula for compound interest A = P(1 +")". Find the number of years (to the nearest tenth) it will take $21,000 to grow to $35,000 at 3% interest compounded quarterly. 35000 = 21000 (1 + 0.03) 4t 4 21000(1+.03/4) (4*17.1)= 35000 35 21000 = (1 + 0:03) 7 = (1.0075)4t In = In(1.0075) 4t In = 4t In (1.0075) In 35 In = 4t In (1.0075) t= 17.1 years 4ln (1.0075) How to put it in your calculator: In (35/21) / (4 In(1.0075) ) = 17.09129.3. To solve the following problem, refer to the formula for compound interest A = P(1+!)". Find the number of years (to the nearest tenth) it will take $25,000 to grow to $32,000 at 3% interest compounded monthly