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Answer:</h2><h2>
The percentage of the family’s total annual electricity that is used to run the two air conditioners for the three summer months = 19.4 %</h2>
Explanation:
Average electricity consumed per month = 900 kWh
The family cools their house for three months during the summer with two window-unit air conditioners
The power consumed by one window-unit air conditioners = 350 kWh
The power consumed by two window-unit air conditioners = 350(2) = 700 kWh
Power consumed for two air conditioners for the three summer months = 700 (3) = 2100 kWh
Total power consumed for 1 year = 900 (12) = 10800kWh
The percentage of the family’s total annual electricity that is used to run the two air conditioners for the three summer months =
= 19.4 %
Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.
We have the following equation representing the half-life decay:

A is the resulting amount after t time
Ao is the initial amount = 50 mg
t= Elapsed time
t half is the half-life of the substance = 14.3 days
We replace the know values into the equation to have an exponential decay function for a 50mg sample

That would be the answer for a)
To know the P-32 remaining after 84 days we have to replace this value in the equation:

So, after 84 days the P-32 remaining will be 0.85 mg
The answer is c hopefully I helped you