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Question
12
3. A new television depreciates \$120 per year, and it is worth \$515 after seven years. Find a
function that describes the value of this television, if x is the age of the television in years. What
will the cost of the television be in thirteen years? If you had bought the television four years
ago, what was its selling price?

"A new television depreciates \$120 per year, and it is worth \$515 after seven years."
total depreciation after 7 years: 7×\$120 = \$840
Purchase price = current value + total depreciation = \$515 + \$840 = \$1,355

"Find a function that describes the value of this television, if x is the age of the television in years."
f(x) = 1,355 - 120x

"What will the cost of the television be in thirteen years?"
13·\$120 > \$1,355
After thirteen years, the television has no residual value.

"If you had bought the television four years ago, what was its selling price?"
I'm not sure what they mean by selling price, as the price of a new television was already found to be \$1,355.
If they mean "how much could you sell it for today," its residual value is
f(4) = 1,355 - 120·4 = \$875

Word Problems

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#### Janet Yang

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Word problems are my favorite type of math questions! I would not feel comfortable answering questions that require specialized knowledge (Physics, Statistics, etc.) because I have not studied these in depth.

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I tutor students (fifth through twelfth grades) and am a Top Contributor on Yahoo!Answers with over 24,000 math solutions.

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