Question 62490
400*(1.2^n)=680*(.85^n)
1.2^n=1.7(0.85^n)
Take the log of both sides to get:
nlog(1.2) = log1.7 + nlog0.85
n[log(1.2)+log(0.85)]=log(1.7)
n=[log(1.7)]/[log(1.2)+log(0.85)]
n=26.795851...
Cheers,
Stan H.