<u>Solution-</u>
Let's assume, the rate of interest of $8000 is x%,
then the rate of interest of $17000 is (x+0.3x) =1.3x%
Interest earned by $8000,
Interest earned by $17,000,
According to the question,
∴ Rate of interest of $8000 is 1.96% and rate of interest of $17000 is (1.3×1.96) =2.55%
CPI in 1960 = 29.6
CPI in 1980 = 82.4
Growth (%) in CPI = × 100
⇒ Growth (%) in CPI = × 100
⇒ Growth (%) in CPI = 178.3783.. %
⇒ Growth (%) in CPI = 178.4%
Now, we know that price of frozen chicken pie in 1960 = $0.28
Also, we know that over 1960 to 1980, frozen chicken pie price grew at the same rate as CPI
Hence, Price of Chicken Pie in 1980 = Price of Chicken Pie in 1960 × (1 + Growth in CPI)
⇒ Price of Chicken Pie in 1980 = 0.28 × (1 + 178.4%)
⇒ Price of Chicken Pie in 1980 = 0.28 + (0.28 × 178.4%)
⇒ Price of Chicken Pie in 1980 = 0.28 + 0.49952
⇒ Price of Chicken Pie in 1980 = 0.28 + 0.50
⇒ Price of Chicken Pie in 1980 = $0.78
Hence, price of chicken pie in 1980 would be ~$0.78