compound interest equation for annually compounded

A=final amount
P=principal
r=rate in decimal
t=time in years
given that
A=1550
P=1000
r=5.5%=0.055
find t

divide both sides by 1000

take ln of both sides

use ln rule 

divide both sides by ln(1.055)

using a calculator, we get that t=8.18544 yrs
so about 8.2yrs
Sorry about my first answer then it would 20% because if you take 30 and divide 20% you'll get 6 so again sorry I was wrong 20 percent though is right.
Wouldn't it be 150 cubic centimeters? Since it has the same area of base and height, it would be the same prism.
Just put it in the calculator and divide 4 by 5 then do 3 by 5 and keep on
Probabilty = 12×(1/12)^3=1/144