Question

If you deposit $8000 into an account paying 7% annual interest compounded quarterly, how long until there is $12400 in the account?

Answer 1

$ammount = principle {(1 + \frac{rate}{100}) }^{time} \\ = 12400 = 8000 ({1 + \frac{7}{100} })^{x} \\ 1.55 = {1.07}^{x} \\ = log_{1.07}(1.55) = x \\ = x = 6.4 \: quater years$
here is ur answer .
time is 1.4 years
need to use log and formule