The radioactive substance uranium-240 has a half-life of 14 hours. The amount
A(t) of a sample of uranium-240 remaining (in grams) after t hours is given by the following exponential function.
At = 3900(1/2) t/14
Find the initial amount in the sample and the amount remaining after 40 hours.
Round your answers to the nearest gram as necessary.

PLEASE HELP ASAP

Respuesta :

we are given

[tex] A(t)=3900(\frac{1}{2})^{\frac{t}{14}} [/tex]

(a)

For finding initial amount , we can set t=0

and find A(t)

[tex] A(0)=3900(\frac{1}{2})^{\frac{0}{14}} [/tex]

[tex] A(0)=3900(\frac{1}{2})^{0} [/tex]

[tex] A(0)=3900 [/tex]

so, initial amount is 3900 grams..........Answer

(b)

We can plug t=40

and find A(t)

[tex] A(40)=3900(\frac{1}{2})^{\frac{40}{14}} [/tex]

[tex] A(40)=538 [/tex]

so, the amount remaining after 40 hours is 538 grams...........Answer

Answer:

To solve this problem, we just need to substitute the right value for the variable time.

The given expression is

[tex]A(t)=3900(\frac{1}{2} )^{\frac{t}{14} }[/tex]

Where the initial condition is determined when [tex]t=0[/tex].

[tex]A(t)=3900(\frac{1}{2} )^{\frac{0}{14} }=3900(1)=3900[/tex]

Therefore, the initial amount is 3900 grams.

Then, after 40 hours refers to [tex]t=40[/tex]

[tex]A(t)=3900(\frac{1}{2} )^{\frac{40}{14} } \approx 538.24[/tex]

Therefore, after 40 hours, there's 538.24 grams remaining, approximately.