Answer:
your answer should be 102kg i could be wrong.
Answer:
The differential equation is 
Step-by-step explanation:
Differential equation for the rate of change in radiation level:
Radiation level is R.
Rate of change indicates that the radiation level R varies in function of time t, which mathematically means that we have:

After the reactor is shut down, the radiation from the nitrogen-17 decreases in such a way that the rate of change in the radiation level is directly proportional to the radiation level.
Rate of change is k. Decreases means that k is negative. Proportional to the radiation level of R means that -k multiplies R. So the differential equation is:

Actually, this answer would be true. Why?
The first equation is: a(sub <em>n</em>) = 8, 13, 18, 23
The second is: a(sub 1)=8 ; a(sub <em>n</em>)= a(sub <em>n</em>-1)+5
if you wish to find the second term, plug two into the equation for <em /><em>n</em>
8+5=13
to find the third, plug the second term, 13, in for <em>n.</em>
13+5=18.
Hope this helped! I know it's a bit on the late side, but at least you can get the general idea!