I think it would be 16.95 Hope this help you in someway.
Answer:
from those are similar, the ratio of side will be 40/24=x/20 so x=33.3333 is equal 33 and one-third.
The band has sold 1,890,000 copies or 1.89 x 10^6
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
