Problema Solution
The cost of a High Definition televisoin now averages $1200, but the cost is decreasing about 15% each year. In how may years with the cost be under $500?
Answer provided by our tutors
The cost now: $1,200
After 1 year: 1,200*(1 - 0.15) = 1,200*0.85
After 2 years: 1,200*0.85^2
After n years: 1,200*0.85^n
Let n represent the number of years
1,200*0.85^n <= 500
........
........
n => 5.39 years
If we assume that n is integer we can conclude that in 6 years the cost will be under $500.
Indeed: 1,200*0.85^6 = $452.58 < 500.