a family buys a car for $20,000 the value of the car decreases by 18% each year after six years the family wants to sell the car they should they sell it for 4000 explained

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the sunflower? ? plz write a proportion to solve i will give you 100 points