A radioactive substance decays exponentially. A scientist begins with 140 milligrams of a radioactive substance. After 25 hours, 70 mg of the substance remains. How many milligrams will remain after 35 hours

Therefore 53.05 mg will remain of the given radioactive substance after 35 hours.

Step-by-step explanation:

Radioactive Decay:

Integrating both sides

                 [ ]

When t=0, = initial amount

Therefore the decay equation is

Given that, = Initial amount of the radioactive substance= 140 mg

After 25 hours, 70 mg of substance remains.

N= 70 mg, t=25 hours

               [  ]

The decay equation becomes

Now putting t= 35

   = 53.05 mg

Therefore 53.05 mg will remain of the given radioactive substance after 35 hours.