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3.3.2: Proving Average Rate of Change
Lupita wants to buy a boat that will have the best resale
value after 3 years.
1. At one boat dealer, she found a boat she likes that
sells for $15,000 and depreciates at a rate of 30%
per year. What will be the value of the boat after 3
years?
2. At another dealer, she found a boat that costs
$12,000 and depreciates at a rate of 20% per year.
What will be the value of the boat after 3 years?
3. Which boat will have the greater value in 3 years?
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3.3.2: Proving Average Rate of Change
1. At one boat dealer, she found a boat she likes that
sells for $15,000 and depreciates at a rate of 30%
per year. What will be the value of the boat after 3
years?
• When the boat is new, it is worth $15,000; then it
depreciates at a rate of 30% each year.
• Create a table to show the decrease in value for
the first 3 years.
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3.3.2: Proving Average Rate of Change
Year
Value of Boat A, in dollars ($)
0
15,000
1
15,000(0.70) = 10,500
2
10,500(0.70) = 7350
3
7350(0.70) = 5145
• Boat A will be worth $5,145 after 3 years.
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3.3.2: Proving Average Rate of Change
2. At another dealer, she found a boat that costs
$12,000 and depreciates at a rate of 20% per year.
What will be the value of the boat after 3 years?
• When the boat is new, it is worth $12,000; then it
depreciates at a rate of 20% each year.
• Create a table to show the decrease in value for
the first 3 years.
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3.3.2: Proving Average Rate of Change
Year
Value of Boat B, in dollars ($)
0
12,000
1
12,000(0.80) = 9600
2
9600(0.80) = 7680
3
7680(0.80) = 6144
• Boat B will be worth $6,144 after 3 years.
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3.3.2: Proving Average Rate of Change
3. Which boat will have the greater value in 3 years?
• Boat A will be worth $5,145 after 3 years.
• Boat B will be worth $6,144 after 3 years.
• Boat B will be worth more than Boat A after 3
years.
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3.3.2: Proving Average Rate of Change