Work is provided in the image attached.
Although you did not include units, I just used centimeters.
However, if there were no units, then just put your answer.
If you do not understand my work,
please ask me in the comments below.
In scientific notation, just move the decimal point over however many numbers are in the power.
In 7.003 • 10^4, move the decimal point over 4 places to the right, (or left if it's negative) making it 70,030
There are eight, if I'm understanding the question correctly. 8 is in the ten thousands place, at least
For this case we have an equation of the form:
y = A * (b) ^ t
Where,
A: initial amount
b: decrease rate
t: time in years.
Substituting values we have:
7 = A * (0.5) ^ ((1/20) * t)
For t = 45 years we have:
7 = A * (0.5) ^ ((1/20) * 45)
Clearing A:
A = 7 / ((0.5) ^ ((1/20) * 45))
A = 33.3
Answer:
the density of the substance when it was deposited 45 years ago was:
A = 33.3 milligrams per square centimeter
78
because 5 times 2 equals 10 so then u times 39 times 2 and get 78
