1/10 of 30000 is 3000 because 30000 divided by 10 is 3000.
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:

Answer:
It appears to be substitution
Step-by-step explanation:
I think you are talking about system of equations
Answer:
provided an easy explanation to give answer below
Step-by-step explanation:
prime numbers are only divisible by 1 and themselves.
2 - 10 prime numbers are
2 3 5 and 7
full list up to 81
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 and 79