Question 1140795
A=Aob^t
800=500*b^1
b=8/5=1.6
A5=500(1.6)^5=5242.88=5243

20000=500*1.6^t
40=1.6^t
log 40=t log 1.6
log 40/log 1.6=t=7.85 hours