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Answer:
The wide of the city is 10.7km
Step-by-step explanation:
To solve this we first have to know the formula to calculate the area of a square
a = area = 115 km²
s = side
a = s * s
now we replace with the known values
115 km² = s * s
115 km² = s²
√(115 km²) = s
10.724km = s
Round to the nearest tenth
s = 10.724km = 10.7km
The wide of the city is 10.7km
To solve this we are going to use the half life equation

Where:

is the initial sample

is the time in years

is the half life of the substance

is the remainder quantity after

years
From the problem we know that:



Lets replace those values in our equation to find

:




We can conclude that after 1600 years of radioactive decay, the mass of the 100-gram sample will be
91.7 grams.
Answer choice D, A,B, and C both equal 3.