Two town on a map are 2 1/4 inches apart.the actual distance between the towns is 45 miles. Which of the following could be the
2 answers:
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Answer:
It would take 24 minutes for the element to decay to 50 grams
Step-by-step explanation:
The equation for the amount of the element present, after t minutes, is:
In which Q(X) decays radioactively with a half life of 12 minutes.(0) is the initial amount and r is the rate it decreases.
Half life of 12 minutes
This means that
So
If there are 200 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 50 grams?
This is t when Q(t) = 50. Q(0) = 200.
It would take 24 minutes for the element to decay to 50 grams
A rectangle has a perimeter of length + length + width + width.
L = length of the fence.
W = width of the fence.
so the perimeter will be L+L+W+W or 2L+2W or 2(L+W).
now, we know that 120 ⩽ 2(L+W).
we also know that 168 ⩾ 2(L+W)
and we also know that whatever the length is, is twice the width, or L = 2W.
L = length of the fence.
W = width of the fence.
so the perimeter will be L+L+W+W or 2L+2W or 2(L+W).
now, we know that 120 ⩽ 2(L+W).
we also know that 168 ⩾ 2(L+W)
and we also know that whatever the length is, is twice the width, or L = 2W.
First, let's establish a ratio between these two values. We'll use that as a starting point. I personally find it easiest to work with ratios as fractions, so we'll set that up:
To find the distance <em>per year</em>, we'll need to find the <em>unit rate</em> of this ratio in terms of years. The word <em>unit</em> refers to the number 1 (coming from the Latin root <em>uni-</em> ); a <em>unit rate</em> involves bringing the number we're interested in down to 1 while preserving the ratio. Since we're looking for the distance the fault line moves every one year, we'll have to bring that 175 down to one, which we can do by dividing it by 175. To preserve our ratio, we also have to divide the top by 175:
We have our answer: approximately 0.14 cm or 1.4 mm per year
To find the distance <em>per year</em>, we'll need to find the <em>unit rate</em> of this ratio in terms of years. The word <em>unit</em> refers to the number 1 (coming from the Latin root <em>uni-</em> ); a <em>unit rate</em> involves bringing the number we're interested in down to 1 while preserving the ratio. Since we're looking for the distance the fault line moves every one year, we'll have to bring that 175 down to one, which we can do by dividing it by 175. To preserve our ratio, we also have to divide the top by 175:
We have our answer: approximately 0.14 cm or 1.4 mm per year