Answer:
60.5 milligrams per square centimeter First, determine how many half lives have expired by dividing the time by the half-life. So: 55/20 = 2.75 That means that only 2^(-2.75) = 0.148650889 = 14.8650889% of the original substance remains. So just divide the amount remaining by 0.148650889 to get the original amount. 9 / 0.148650889 = 60.5445419 So originally, there was 60.5 milligrams per square centimeter 55 years ago.
Do u have a problem that went with this?
You normally use pie in equation that had the circumference or radius or diameter. !<span />
Step-by-step explanation:
.20 times 2000 is your answer = $40 is 20% of 2000.
