Question
At the show a basketball card dealer tells you that a vintage card increases in value by a factor of 10 every 9 years.If the card is now worth $32, how long ago did she buy it?(Hint: Remember that the value is multiplied by 10 every 9 years, not every year.)
2nd Question
Estimate the effective yield of an investiment in this basketball card.
2nd Question
Estimate the effective yield of an investiment in this basketball card.
Answers
Reiny
You are missing information here.
The way it is worded we would have to know what the initial value of the card was.
I would use the equation
Value = a(10)^(t/9) where a is the initial value, and t is the number of years
32 = a(10^(t/9)
t/9 = log(32/a) / log 10
t/9 = log(32/a) because log 10 = 1
once you have a, you can finish it.
The way it is worded we would have to know what the initial value of the card was.
I would use the equation
Value = a(10)^(t/9) where a is the initial value, and t is the number of years
32 = a(10^(t/9)
t/9 = log(32/a) / log 10
t/9 = log(32/a) because log 10 = 1
once you have a, you can finish it.
Brittany
wait I forgot to add that she bought the card origionally for $1
Reiny
then as I said replace a with 1 in
t/9 = log(32/a) to get
t = 9log32
= 13.55 years
t/9 = log(32/a) to get
t = 9log32
= 13.55 years