The amount of the substance (At) at any time t is calculated through the equation,
At = (A0)(e^-kt)
where A0 is the initial amount and k is constant.
For the half-life,
ln (At / A0) = ln 0.5 = -k(5270 years)
The value of k is 1.3153x10^-4 / year.
Substituting this value to the same equation, where At = 0.25A0
ln 0.25 = -(1.3153 x 10^-4)(t)
The value of t from this equation is 10540 years. The closest value to this is letter A.
Answer:
The value is 64.
Step-by-step explanation:
Answer:
Step-by-step explanation:
Surface area of a cylinder = 2 x 3.14 x rh + 2 x 3.14 x r^2
S.A. = (2 x 3.14 x 3 x 18.2) + (2 x 3.14 x 3^2)
S.A. = 399.4cm^2
