I think you answer would be 6400

yay, doubling time this is assuming that the interest rate is such that it doubles every 8 years, not like a magical double that happense every 8 years the equation is [latex]A=P(2)^frac{t}{d}[/latex] A=final amount P=initial amount t=time elapsed in years d=doubling time in years ok A=A P=100 d=8yrs t=49yrs so [latex]A=100(2)^frac{49}{8}[/latex] use your calcuator for that one A≈6979.24948 rounded to nearest cent A=$6979.25 there will be 6979.25 in the account after 49 years if you had a magic account where it doubles only after 8 years have elapsed then find how many doubling times have passed 49/8=6.125 so only 6 doubling times that is 100 times 2⁶ or 64000 in the account if it is an interest rate such that it eventually will double after 8 years, every 8 years, then the amount is $6979.25 if it magically doubles only after 8 years have elapsed (like at 7.999 years, no double and at 8 yrs, magic, double) there will be $6400 in the account