Answer:
answer
Step-by-step explanation:
step by step explanation
Answer:
56 is 70% of 80 students.
Step-by-step explanation:
70% = 0.7
56 divided by 0.7 = 80
3 equivalent ratios or 5/2
10 /4
20/8
30/12
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
20 and 45x
We look for a number that can go into both numbers.
5 into 20 is 4 and 5 into 45x is 9x.
5: 20 45x
4 9x
So no other number can go into 4 and 9x again.
So the GCF of 20 and 45x is 5.
Hope this explains it.
