A field is to be fertilized at a cost of $0.08 per square yard. The rectangular part of the field is 95 yards long and the diame
ter of each semicircle is 49 yards. Find the cost of fertilizing the field. Use 3.14 for π
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Answer:
The half-life of the radioactive substance is 135.9 hours.
Step-by-step explanation:
The rate of decay is proportional to the amount of the substance present at time t
This means that the amount of the substance can be modeled by the following differential equation:
Which has the following solution:
In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.
After 6 hours the mass had decreased by 3%.
This means that . We use this to find r.
So
Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So
The half-life of the radioactive substance is 135.9 hours.