60-12-18-2-8=20
=48-18-2-8
=30-2-8
=28-8
=20
So, 20 students don't take either of these subjects.
Answer:
8978 grams
Step-by-step explanation:
The equation to find the half-life is:
N(t) = amount after the time <em>t</em>
= initial amount of substance
t = time
It is known that after a half-life there will be twice less of a substance than what it intially was. So, we can get a simplified equation that looks like this, in terms of half-lives.
or more simply
= time of the half-life
We know that = 35,912, t = 14,680, and =7,340
Plug these into the equation:
Using a calculator we get:
N(t) = 8978
Therefore, after 14,680 years 8,978 grams of thorium will be left.
Hope this helps!! Ask questions if you need!!
C. Photographer A’s equipment fee is $25 less than Photographer B’s