Time Formula equivalent

Question

What is the formula if a simple interest rate is equivalent to a discount rate timeline? The question is: If a simple interest rate of 21 % per annum, is equivalent to a discount rate of 19% per annum, the the lenght of time under consideration is....

Answer 1

fv=p(1+int/c)^(nt)

future value

time line=n

yrly=t

p=premium

int

compounded

fv for $1000=1000(1+.21)^(1)=1210

.19 =1190

/=1.0168..................yrs. For 19% to equal 21% (interest).