Answer:
I believe the answer is 1659
Step-by-step explanation:
395 ÷ 20 = 19.75
19.75 × 84 = 1659
Let
x------> <span>speed on the bicycle
y------> </span><span>speed walking
we know that
</span>x=6+y------> equation 1<span>
speed=distance /time-------> time=distance/speed
1/y=2.5/x-------> y=x/2.5------> x=2.5y-------> equation 2
equals 1 and 2
6+y=2.5y-----> 2.5y-y=6------> 1.5y=6-----> y=6/1.5-----> y=4 mi/h
x=6+y-----> x=6+4-----> x=10 mi/h
the answer is
the speed walking is 4 mi/h
</span><span>
</span>
The amount of the substance (At) at any time t is calculated through the equation,
At = (A0)(e^-kt)
where A0 is the initial amount and k is constant.
For the half-life,
ln (At / A0) = ln 0.5 = -k(5270 years)
The value of k is 1.3153x10^-4 / year.
Substituting this value to the same equation, where At = 0.25A0
ln 0.25 = -(1.3153 x 10^-4)(t)
The value of t from this equation is 10540 years. The closest value to this is letter A.
Answer:

Step-by-step explanation:
Given expression
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Answer:
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Step-by-step explanation: