Stereo Inc. sells a stereo system for $$400$ down and monthly payments of $$50$ for the next $4$ years. If the interest rate is $1\mathrm{.}25\%$ per year, find:

a$)$ The cost of the stereo.

Answer $=$

Hint: The answer is a dollar amount and should include a dollar sign and have exactly two decimal places.

b$)$ The total amount of interest paid.

Answer $=$

Hint: The answer is a dollar amount and should include a dollar sign and have exactly two decimal places.

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