On a snowy evening only 2/3 of the registered students in Bob's chess
1 answer:
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Answer:
1) The third option.
2) The last option.
Step-by-step explanation:
1) f(x) is greater on the interval (0,3), which is opened, because if you substitute you obtain the following result:
2) If , you obtain that:
Therefore:
Answer:
A) 277 million years
Step-by-step explanation:
Here, decay of U-238 is first order reaction. (since most of the nuclear decays are first order).
so, the equation t = × ln(
)
where, t = time from start of reaction
k = reaction constant
A(0) = initial concentration; A = present concentration.
⇒ 4.5 billion = 4500 million years = × ln2.
Now, given 95.82% of parent U-238 isotope is left.
⇒ t = × ln(
)
t = × ln(
)
⇒ t ≅ 277 million years.