Question 180563
assuming the interest rate is the same for both amounts invested
:
{{{8000+8000x+(8000+8000x)x+2500+2500x=11445}}}
:
{{{8000+8000x+8000x+8000x^2+2500+2500x=11445}}}
:
{{{8000x^2+18500x-945=0}}}
:
x=.05 and -2.36
:
throw out the negative
:
interest rate is {{{.05(100)=highlight(5)}}}%
:
*[invoke solve_quadratic_equation 8000, 18500, -945]