Alvin's age + Elga's age = 84
2R + R = 84
3 R = 84
3/ 3 R = 84/ 3
R = 28
Elga's age is 28
Answer:
A
Step-by-step explanation:
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

B and C are the same thing and they would be the two representations of the conversion that shows 12 inches is equivalent to 1 foot, so B and C are your answers
Answer:1
Step-by-step explanation:heheh