If 
is the amount of strontium-90 present in the area in year 
, and it decays at a rate of 2.5% per year, then
Let 
be the starting amount immediately after the nuclear reactor explodes. Then
or simply
So that after 50 years, the amount of strontium-90 that remains is approximately
or about 28% of the original amount.
We can confirm this another way; recall the exponential decay formula,
where is measured in years. We're told that 2.5% of the starting amount 
decays after 1 year, so that
Then after 50 years, we have
Answer:
She has 480 red roses in total
Step-by-step explanation:
Rate of change = difference in y over difference in x.
Rate of change = (33-20)/(3-1) = 13/2
Rate of change = (48-33) /(5-3) = 15/2
The rates are not the same so it isn’t linear.
The rate of change for x=3 and x = 5 is greater.
