Question

Math Help Please explain the questions How long will it take for the balance of an account to double if the savings account earns 0.75% annual interest compounded monthly? Hint: Set up the problem using the formula: = (1 + r/n).                                      Solve. Give BOTH the exact answer and approximate answer for x. The attachment is below for this second question.                                                                                                          Write as a single logarithm.
                 4 ∙ log3 + log2

Answer 1

(See attached formula)
Years = log (total / principal) / n*log(1 + rate/n) where n = compounding periods per year
Years = log (total / principal) / n*log(1 + rate/n)
Rate of .75% = .0625 per month
We'll say we want total = 200 and principal = 100
Years = log (200 / 100) / 12*log(1 + rate/n)
Years = log (2) / 12 * log (1 + .0625/12)
Years = 0.3010299957 / 12 *  0.0022560803
Years = 0.3010299957 / 0.0270729635
Years = 11.1192110871
I don't think that's right
The interest rate is REALLY low. (Less than 1%)
Rate = .75 and .0075 when in a formula
Years = log (2) / 12 * log (1 + .0075/12)
Years = log (2) / 12 * log( 1.000625)
Years = 0.3010299957 / 12 * 0.0002713493
Years = 0.3010299957 / 0.0032561912
Years = 92.4485010892
THAT seems a more likely answer with such a low interest rate.