Answer:
- 9800(0.80)^t
- 2200(0.85)^t
- 25%
Step-by-step explanation:
You want the missing formulas and rate in the chart showing rate of decrease, value now, and value in t years for different items.
Rate of decrease
If r is the rate of decrease, the relationship between table values is ...
value in t years = (value now)(1 -r)^t
Application
Car: value now is 9800, and r = 0.20, so ...
value in t years = 9800(0.80)^t
Boat: value now is 2200, and r = 0.15, so ...
value in t years = 2200(0.85)^t
Skates: multiplier is (1 -r) = 0.75, so ...
rate of decrease = 1 -0.75 = 25%
