algebra word problem on consumer price index?

Question

i'm having trouble with this word problem. i know there's 2-steps to solve it. thanks for the help.

table 1.2
year--> 1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, 2000
CPI--> 29.6, 31.5, 38.8, 53.8, 82.4, 107.6, 130.7, 153.5, 172.2

use table 1.2 to estimate the percent change in prices from 1965 to 1995. in 1965 a gallon of gas cost about $0.30. if this price had kept pace w/ the CPI, what would a gallon of gas have cost in 1995?

Answer 1

Ok, you really only need two values for the first part of the problem. CPI for 1965 (31.5) and CPI for 1995 (153.5).

Percent change between 31.5 and 153.5 is:

(153.5 / 31.5) = 4.873 = 487.3%

If the gas cost $0.30 in 1965, and it kept pace with the CPI, it would also go up by 487.3%.

0.30 * 4.873 = 1.4619 = $1.46

A gallon of gas in 1995 should cost $1.46

Answer 2

it is (153.5/31.5)*0.30=$1.46