Answer:
The bones were 12,485 years old at the time they were discovered.
Step-by-step explanation:
Amount of the element:
The amount of the element after t years is given by the following equation, considering the decay rate proportional to the amount present:

In which A(0) is the initial amount and k is the decay rate, as a decimal.
The radioactive element carbon-14 has a half-life of 5750 years.
This means that
, and we use this to find k. So







So

A scientist determined that the bones from a mastodon had lost 77.8 % of their carbon-14. How old were the bones at the time they were discovered?
Had 100 - 77.8 = 22.2% remaining, so this is t for which:

Then






The bones were 12,485 years old at the time they were discovered.
Answer:
350 in²
Step-by-step explanation:
Assuming the solid likes are the design. So we see two parallelograms there.
Area of 1 parallelogram = base x height. Since we have a joint height, we will multiply the total height with the base (both have the same base length) to get the area of 1 design.
1 design = 3.5 x 2 = 7 in²
50 designs = 7 x 50 = 350 in²
In guessing it's 2,106.......
The answer to this question is 8.86666666667