<span>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.</span>
The range is the difference between the highest and lowest number in a list of numbers. For example:
3 7 8 2 0. The lowest number is 0, and the highest is 8. The difference is 8, which is also known as the range.
Answer:
C. 
Step-by-step explanation:
When two polygons are considered similar, the ratio of their corresponding sides would also be equal.
Since ∆ABC and ∆ADE are similar, 
Cross multiply
Divide both sides by 7 to find AB
Answer:
x=2 y=1
Step-by-step explanation:
Solve the equations by substituting y=6x-11 into -2x-3y=-7.
-2x-3(6x-11)=-7
-2x-18x+33=-7
-20x+33=-7
-20x=-7-33
-20x=-40
x=2
To find y, substitute this value into the equation and solve for y.
y=6(2)-11
y=12-11
y=1
Answer:
22 people per square mile
Step-by-step explanation:
