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
Alejandro is correct because you do not need to add another number to 76.518, as Jiro did, but you need to round it to the nearest tenth.
Glad I could help, and good luck!
Answer:
2/5 okkkkkkkkkkkkkkkkkkkkk
Answer: 5.53
Step-by-step explanation:
this is a straight forward addition
2.5+3.03 =5.53
to be clear or to specify, use the decimal point to make the sum:
2.5 = 2 + 0.5 and 3.03 = 3 + 0.03
2+3= 5 and 0.5 + 0.03 = 0.53
5 + 0.53 = 5.53 (but this is to long just to make it clear)
Answer:
the answer is A and D
Step-by-step explanation:
