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.
Question 13 is 14 x is 14
Hi so I’m going to answer your problem which is “List three words or phrases used in real life that indicate positive numbers,” so let’s get right into it!
You can it as temperature too, today is 80+ degrees outside!
You can also use an the floors of which an elevator takes you in which direction it takes upwards or downwards like “take the elevator 4 floors up”
You can also use gas as a thing we use in real life, it also indicates numbers
Like gas is __ a gallon cheaper this week
6 dollars doesn't change, it's 6 per customer
the one that changes is cost of apples, 2 per pound where pounds is x
2 times number of pounds=2 times x or 2x
so total cost=admission+aples=6+2x or y=2x+6 where y=total cost
so B is the answer
When writing the congruent triangles, the otder of the letters is EXTREMELY important.
This is because, each angle in the first triangle is congruent to its corresponding angle in the second triangle and each side in the first triangle is congruent to its corresponding sode in the second triangle.
Now, we are given that triangle CDA is congruent to triangle XYZ.
Based on the above explanation, we can conclude that:
angle C is congruent to angle X
angle D is congruent to angle Y
angle A is congruent to angle Z
