Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
Based on the calculations, the approximate area covered by the reservoir is equal to 0.28 km².
<h3>What is the area of a circle?</h3>
The area of a circle simply refers to the space occupied or the region enclosed by a circle within its boundary, and in a two-dimensional plane.
<h3>How to calculate the area of a circle?</h3>
Mathematically, the area of a circle is calculated by using this formula:
Area = πr²
<u>Where:</u>
r is the radius of a circle.
<u>Given the following data:</u>
Diameter of circle = 0.6 kilometer.
π = 3.14.
Radius = 0.6/2 = 0.3 km.
Substituting the given parameters into the formula, we have;
Area = π × 0.3²
Area = 3.14 × 0.09
Area = 0.28 km².
Read more on circle here: brainly.com/question/14478195
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Answer:
distance from the sea.
ocean currents.
direction of prevailing winds.
shape of the land (known as 'relief' or 'topography')
distance from the equator.
the El Niño phenomenon.
Explanation:
Fauna.
Fauna means animal life.
